diff --git a/Gruntfile.js b/Gruntfile.js
index cf7c78a1b..713eb3c4b 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -53,7 +53,7 @@ module.exports = function (grunt) {
       },
       "include-minified-script": {
         cmd: "sed",
-        args: ["-i", "s/authelia\.js/authelia.min.js/", `${buildDir}/server/src/views/layout/layout.pug`]
+        args: ["-i", "s/authelia.\(js\|css\)/authelia.min.\1/", `${buildDir}/server/src/views/layout/layout.pug`]
       }
     },
     copy: {
diff --git a/client/src/lib/firstfactor/FirstFactorValidator.ts b/client/src/lib/firstfactor/FirstFactorValidator.ts
index 175f3c2c8..60a4d17c3 100644
--- a/client/src/lib/firstfactor/FirstFactorValidator.ts
+++ b/client/src/lib/firstfactor/FirstFactorValidator.ts
@@ -3,6 +3,7 @@ import BluebirdPromise = require("bluebird");
 import Endpoints = require("../../../../shared/api");
 import Constants = require("../../../../shared/constants");
 import Util = require("util");
+import UserMessages = require("../../../../shared/UserMessages");
 
 export function validate(username: string, password: string,
   redirectUrl: string, $: JQueryStatic): BluebirdPromise<string> {
@@ -24,11 +25,15 @@ export function validate(username: string, password: string,
         password: password,
       }
     })
-      .done(function (data: { redirect: string }) {
-        resolve(data.redirect);
+      .done(function (body: any) {
+        if (body && body.error) {
+          reject(new Error(body.error));
+          return;
+        }
+        resolve(body.redirect);
       })
       .fail(function (xhr: JQueryXHR, textStatus: string) {
-        reject(new Error("Authetication failed. Please check your credentials."));
+        reject(new Error(UserMessages.AUTHENTICATION_FAILED));
       });
   });
 }
diff --git a/client/src/lib/firstfactor/index.ts b/client/src/lib/firstfactor/index.ts
index 91de7e001..0c5f9828d 100644
--- a/client/src/lib/firstfactor/index.ts
+++ b/client/src/lib/firstfactor/index.ts
@@ -5,6 +5,7 @@ import { Notifier } from "../Notifier";
 import { QueryParametersRetriever } from "../QueryParametersRetriever";
 import Constants = require("../../../../shared/constants");
 import Endpoints = require("../../../../shared/api");
+import UserMessages = require("../../../../shared/UserMessages");
 
 export default function (window: Window, $: JQueryStatic,
   firstFactorValidator: typeof FirstFactorValidator, jslogger: typeof JSLogger) {
@@ -23,18 +24,14 @@ export default function (window: Window, $: JQueryStatic,
   }
 
   function onFirstFactorSuccess(redirectUrl: string) {
-    jslogger.debug("First factor validated.");
-      window.location.href = redirectUrl;
+    window.location.href = redirectUrl;
   }
 
   function onFirstFactorFailure(err: Error) {
-    jslogger.debug("First factor failed.");
-    notifier.error("Authentication failed. Please double check your credentials.");
+    notifier.error(UserMessages.AUTHENTICATION_FAILED);
   }
 
-
   $(window.document).ready(function () {
-    jslogger.info("Enter first factor");
     $("form").on("submit", onFormSubmitted);
   });
 }
diff --git a/client/src/lib/reset-password/reset-password-form.ts b/client/src/lib/reset-password/reset-password-form.ts
index 12f60d777..888026f62 100644
--- a/client/src/lib/reset-password/reset-password-form.ts
+++ b/client/src/lib/reset-password/reset-password-form.ts
@@ -1,6 +1,8 @@
 import BluebirdPromise = require("bluebird");
 
 import Endpoints = require("../../../../shared/api");
+import UserMessages = require("../../../../shared/UserMessages");
+
 import Constants = require("./constants");
 import { Notifier } from "../Notifier";
 
@@ -12,8 +14,12 @@ export default function (window: Window, $: JQueryStatic) {
       $.post(Endpoints.RESET_PASSWORD_FORM_POST, {
         password: newPassword,
       })
-        .done(function (data) {
-          resolve(data);
+        .done(function (body: any) {
+          if (body && body.error) {
+            reject(new Error(body.error));
+            return;
+          }
+          resolve(body);
         })
         .fail(function (xhr, status) {
           reject(status);
@@ -26,22 +32,21 @@ export default function (window: Window, $: JQueryStatic) {
     const password2 = $("#password2").val();
 
     if (!password1 || !password2) {
-      notifier.warning("You must enter your new password twice.");
+      notifier.warning(UserMessages.MISSING_PASSWORD);
       return false;
     }
 
     if (password1 != password2) {
-      notifier.warning("The passwords are different.");
+      notifier.warning(UserMessages.DIFFERENT_PASSWORDS);
       return false;
     }
 
     modifyPassword(password1)
       .then(function () {
-        notifier.success("Your password has been changed. Please log in again.");
         window.location.href = Endpoints.FIRST_FACTOR_GET;
       })
       .error(function () {
-        notifier.warning("An error occurred during password reset. Your password has not been changed.");
+        notifier.error(UserMessages.RESET_PASSWORD_FAILED);
       });
     return false;
   }
diff --git a/client/src/lib/reset-password/reset-password-request.ts b/client/src/lib/reset-password/reset-password-request.ts
index 0685e1760..426bad34b 100644
--- a/client/src/lib/reset-password/reset-password-request.ts
+++ b/client/src/lib/reset-password/reset-password-request.ts
@@ -2,11 +2,12 @@
 import BluebirdPromise = require("bluebird");
 
 import Endpoints = require("../../../../shared/api");
+import UserMessages = require("../../../../shared/UserMessages");
 import Constants = require("./constants");
 import jslogger = require("js-logger");
 import { Notifier } from "../Notifier";
 
-export default function(window: Window, $: JQueryStatic) {
+export default function (window: Window, $: JQueryStatic) {
   const notifier = new Notifier(".notification", $);
 
   function requestPasswordReset(username: string) {
@@ -14,7 +15,11 @@ export default function(window: Window, $: JQueryStatic) {
       $.get(Endpoints.RESET_PASSWORD_IDENTITY_START_GET, {
         userid: username,
       })
-        .done(function () {
+        .done(function (body: any) {
+          if (body && body.error) {
+            reject(new Error(body.error));
+            return;
+          }
           resolve();
         })
         .fail(function (xhr: JQueryXHR, textStatus: string) {
@@ -27,25 +32,24 @@ export default function(window: Window, $: JQueryStatic) {
     const username = $("#username").val();
 
     if (!username) {
-      notifier.warning("You must provide your username to reset your password.");
+      notifier.warning(UserMessages.MISSING_USERNAME);
       return;
     }
 
     requestPasswordReset(username)
       .then(function () {
-        notifier.success("An email has been sent to you. Follow the link to change your password.");
+        notifier.success(UserMessages.MAIL_SENT);
         setTimeout(function () {
           window.location.replace(Endpoints.FIRST_FACTOR_GET);
         }, 1000);
       })
       .error(function () {
-        notifier.warning("Are you sure this is your username?");
+        notifier.error(UserMessages.MAIL_NOT_SENT);
       });
-      return false;
+    return false;
   }
 
   $(document).ready(function () {
-    jslogger.debug("Reset password request form setup");
     $(Constants.FORM_SELECTOR).on("submit", onFormSubmitted);
   });
 }
diff --git a/client/src/lib/secondfactor/TOTPValidator.ts b/client/src/lib/secondfactor/TOTPValidator.ts
index 824b591a7..5d845edc5 100644
--- a/client/src/lib/secondfactor/TOTPValidator.ts
+++ b/client/src/lib/secondfactor/TOTPValidator.ts
@@ -3,20 +3,24 @@ import BluebirdPromise = require("bluebird");
 import Endpoints = require("../../../../shared/api");
 
 export function validate(token: string, $: JQueryStatic): BluebirdPromise<string> {
-    return new BluebirdPromise<string>(function (resolve, reject) {
-        $.ajax({
-            url: Endpoints.SECOND_FACTOR_TOTP_POST,
-            data: {
-                token: token,
-            },
-            method: "POST",
-            dataType: "json"
-        } as JQueryAjaxSettings)
-            .done(function (data: any) {
-                resolve(data);
-            })
-            .fail(function (xhr: JQueryXHR, textStatus: string) {
-                reject(new Error(textStatus));
-            });
-    });
+  return new BluebirdPromise<string>(function (resolve, reject) {
+    $.ajax({
+      url: Endpoints.SECOND_FACTOR_TOTP_POST,
+      data: {
+        token: token,
+      },
+      method: "POST",
+      dataType: "json"
+    } as JQueryAjaxSettings)
+      .done(function (body: any) {
+        if (body && body.error) {
+          reject(new Error(body.error));
+          return;
+        }
+        resolve(body);
+      })
+      .fail(function (xhr: JQueryXHR, textStatus: string) {
+        reject(new Error(textStatus));
+      });
+  });
 }
\ No newline at end of file
diff --git a/client/src/lib/secondfactor/U2FValidator.ts b/client/src/lib/secondfactor/U2FValidator.ts
index 66c7751aa..0806e2418 100644
--- a/client/src/lib/secondfactor/U2FValidator.ts
+++ b/client/src/lib/secondfactor/U2FValidator.ts
@@ -4,59 +4,64 @@ import U2f = require("u2f");
 import BluebirdPromise = require("bluebird");
 import { SignMessage } from "../../../../shared/SignMessage";
 import Endpoints = require("../../../../shared/api");
+import UserMessages = require("../../../../shared/UserMessages");
 import { INotifier } from "../INotifier";
 
 function finishU2fAuthentication(responseData: U2fApi.SignResponse, $: JQueryStatic): BluebirdPromise<void> {
-    return new BluebirdPromise<void>(function (resolve, reject) {
-        $.ajax({
-            url: Endpoints.SECOND_FACTOR_U2F_SIGN_POST,
-            data: responseData,
-            method: "POST",
-            dataType: "json"
-        } as JQueryAjaxSettings)
-            .done(function (data) {
-                resolve(data);
-            })
-            .fail(function (xhr: JQueryXHR, textStatus: string) {
-                reject(new Error(textStatus));
-            });
-    });
+  return new BluebirdPromise<void>(function (resolve, reject) {
+    $.ajax({
+      url: Endpoints.SECOND_FACTOR_U2F_SIGN_POST,
+      data: responseData,
+      method: "POST",
+      dataType: "json"
+    } as JQueryAjaxSettings)
+      .done(function (body: any) {
+        if (body && body.error) {
+          reject(new Error(body.error));
+          return;
+        }
+        resolve(body);
+      })
+      .fail(function (xhr: JQueryXHR, textStatus: string) {
+        reject(new Error(textStatus));
+      });
+  });
 }
 
 function startU2fAuthentication($: JQueryStatic, notifier: INotifier, u2fApi: typeof U2fApi): BluebirdPromise<void> {
-    return new BluebirdPromise<void>(function (resolve, reject) {
-        $.get(Endpoints.SECOND_FACTOR_U2F_SIGN_REQUEST_GET, {}, undefined, "json")
-            .done(function (signResponse: SignMessage) {
-                notifier.info("Please touch the token");
+  return new BluebirdPromise<void>(function (resolve, reject) {
+    $.get(Endpoints.SECOND_FACTOR_U2F_SIGN_REQUEST_GET, {}, undefined, "json")
+      .done(function (signResponse: SignMessage) {
+        notifier.info(UserMessages.PLEASE_TOUCH_TOKEN);
 
-                const signRequest: U2fApi.SignRequest = {
-                    appId: signResponse.request.appId,
-                    challenge: signResponse.request.challenge,
-                    keyHandle: signResponse.keyHandle, // linked to the client session cookie
-                    version: "U2F_V2"
-                };
+        const signRequest: U2fApi.SignRequest = {
+          appId: signResponse.request.appId,
+          challenge: signResponse.request.challenge,
+          keyHandle: signResponse.keyHandle, // linked to the client session cookie
+          version: "U2F_V2"
+        };
 
-                u2fApi.sign([signRequest], 60)
-                    .then(function (signResponse: U2fApi.SignResponse) {
-                        finishU2fAuthentication(signResponse, $)
-                            .then(function (data) {
-                                resolve(data);
-                            }, function (err) {
-                                notifier.error("Error when finish U2F transaction");
-                                reject(err);
-                            });
-                    })
-                    .catch(function (err: Error) {
-                        reject(err);
-                    });
-            })
-            .fail(function (xhr: JQueryXHR, textStatus: string) {
-                reject(new Error(textStatus));
-            });
-    });
+        u2fApi.sign([signRequest], 60)
+          .then(function (signResponse: U2fApi.SignResponse) {
+            finishU2fAuthentication(signResponse, $)
+              .then(function (data) {
+                resolve(data);
+              }, function (err) {
+                notifier.error(UserMessages.U2F_TRANSACTION_FINISH_FAILED);
+                reject(err);
+              });
+          })
+          .catch(function (err: Error) {
+            reject(err);
+          });
+      })
+      .fail(function (xhr: JQueryXHR, textStatus: string) {
+        reject(new Error(textStatus));
+      });
+  });
 }
 
 
 export function validate($: JQueryStatic, notifier: INotifier, u2fApi: typeof U2fApi): BluebirdPromise<void> {
-    return startU2fAuthentication($, notifier, u2fApi);
+  return startU2fAuthentication($, notifier, u2fApi);
 }
diff --git a/client/src/lib/secondfactor/index.ts b/client/src/lib/secondfactor/index.ts
index 52875254e..c829dea8b 100644
--- a/client/src/lib/secondfactor/index.ts
+++ b/client/src/lib/secondfactor/index.ts
@@ -9,7 +9,7 @@ import { Notifier } from "../Notifier";
 import { QueryParametersRetriever } from "../QueryParametersRetriever";
 import Endpoints = require("../../../../shared/api");
 import ServerConstants = require("../../../../shared/constants");
-
+import UserMessages = require("../../../../shared/UserMessages");
 
 export default function (window: Window, $: JQueryStatic, u2fApi: typeof U2fApi) {
   const notifierTotp = new Notifier(".notification-totp", $);
@@ -20,7 +20,7 @@ export default function (window: Window, $: JQueryStatic, u2fApi: typeof U2fApi)
     if (redirectUrl)
       window.location.href = redirectUrl;
     else
-      notifier.success("Authentication succeeded. You can now access your services.");
+      notifier.success(UserMessages.AUTHENTICATION_SUCCEEDED);
   }
 
   function onSecondFactorTotpSuccess(data: any) {
@@ -28,7 +28,7 @@ export default function (window: Window, $: JQueryStatic, u2fApi: typeof U2fApi)
   }
 
   function onSecondFactorTotpFailure(err: Error) {
-    notifierTotp.error("Problem with TOTP validation.");
+    notifierTotp.error(UserMessages.AUTHENTICATION_TOTP_FAILED);
   }
 
   function onU2fAuthenticationSuccess(data: any) {
@@ -36,13 +36,11 @@ export default function (window: Window, $: JQueryStatic, u2fApi: typeof U2fApi)
   }
 
   function onU2fAuthenticationFailure() {
-    notifierU2f.error("Problem with U2F validation. Did you register before authenticating?");
+    notifierU2f.error(UserMessages.AUTHENTICATION_U2F_FAILED);
   }
 
   function onTOTPFormSubmitted(): boolean {
     const token = $(Constants.TOTP_TOKEN_SELECTOR).val();
-    jslogger.debug("TOTP token is %s", token);
-
     TOTPValidator.validate(token, $)
       .then(onSecondFactorTotpSuccess)
       .catch(onSecondFactorTotpFailure);
@@ -50,7 +48,6 @@ export default function (window: Window, $: JQueryStatic, u2fApi: typeof U2fApi)
   }
 
   function onU2FFormSubmitted(): boolean {
-    jslogger.debug("Start U2F authentication");
     U2FValidator.validate($, notifierU2f, U2fApi)
       .then(onU2fAuthenticationSuccess, onU2fAuthenticationFailure);
     return false;
diff --git a/client/src/lib/u2f-register/u2f-register.ts b/client/src/lib/u2f-register/u2f-register.ts
index f895bbf60..f66e3c80e 100644
--- a/client/src/lib/u2f-register/u2f-register.ts
+++ b/client/src/lib/u2f-register/u2f-register.ts
@@ -5,6 +5,7 @@ import u2fApi = require("u2f-api");
 import jslogger = require("js-logger");
 import { Notifier } from "../Notifier";
 import Endpoints = require("../../../../shared/api");
+import UserMessages = require("../../../../shared/UserMessages");
 
 export default function (window: Window, $: JQueryStatic) {
   const notifier = new Notifier(".notification", $);
@@ -16,8 +17,12 @@ export default function (window: Window, $: JQueryStatic) {
 
     return new BluebirdPromise<string>(function (resolve, reject) {
       $.post(Endpoints.SECOND_FACTOR_U2F_REGISTER_POST, registrationData, undefined, "json")
-        .done(function (data) {
-          resolve(data.redirection_url);
+        .done(function (body: any) {
+          if (body && body.error) {
+            reject(new Error(body.error));
+            return;
+          }
+          resolve(body.redirection_url);
         })
         .fail(function (xhr, status) {
           reject();
@@ -29,8 +34,6 @@ export default function (window: Window, $: JQueryStatic) {
     return new BluebirdPromise<string>(function (resolve, reject) {
       $.get(Endpoints.SECOND_FACTOR_U2F_REGISTER_REQUEST_GET, {}, undefined, "json")
         .done(function (registrationRequest: U2f.Request) {
-          jslogger.debug("registrationRequest = %s", JSON.stringify(registrationRequest));
-
           const registerRequest: u2fApi.RegisterRequest = registrationRequest;
           u2fApi.register([registerRequest], [], 120)
             .then(function (res: u2fApi.RegisterResponse) {
@@ -47,7 +50,7 @@ export default function (window: Window, $: JQueryStatic) {
   }
 
   function onRegisterFailure(err: Error) {
-    notifier.error("Problem while registering your U2F device.");
+    notifier.error(UserMessages.REGISTRATION_U2F_FAILED);
   }
 
   $(document).ready(function () {
diff --git a/client/test/firstfactor/FirstFactorValidator.test.ts b/client/test/firstfactor/FirstFactorValidator.test.ts
index acae7c0d7..ac8353278 100644
--- a/client/test/firstfactor/FirstFactorValidator.test.ts
+++ b/client/test/firstfactor/FirstFactorValidator.test.ts
@@ -38,7 +38,7 @@ describe("test FirstFactorValidator", function () {
 
     describe("should fail first factor validation", () => {
         it("should fail with error", () => {
-            return should_fail_first_factor_validation("Authetication failed. Please check your credentials.");
+            return should_fail_first_factor_validation("Authentication failed. Please check your credentials.");
         });
     });
 });
\ No newline at end of file
diff --git a/client/test/secondfactor/TOTPValidator.test.ts b/client/test/secondfactor/TOTPValidator.test.ts
index e03b0b9ad..5952eb611 100644
--- a/client/test/secondfactor/TOTPValidator.test.ts
+++ b/client/test/secondfactor/TOTPValidator.test.ts
@@ -5,33 +5,33 @@ import BluebirdPromise = require("bluebird");
 import Assert = require("assert");
 
 describe("test TOTPValidator", function () {
-    it("should initiate an identity check successfully", () => {
-        const postPromise = JQueryMock.JQueryDeferredMock();
-        postPromise.done.yields();
-        postPromise.done.returns(postPromise);
+  it("should initiate an identity check successfully", () => {
+    const postPromise = JQueryMock.JQueryDeferredMock();
+    postPromise.done.yields();
+    postPromise.done.returns(postPromise);
 
-        const jqueryMock = JQueryMock.JQueryMock();
-        jqueryMock.jquery.ajax.returns(postPromise);
+    const jqueryMock = JQueryMock.JQueryMock();
+    jqueryMock.jquery.ajax.returns(postPromise);
 
-        return TOTPValidator.validate("totp_token", jqueryMock.jquery as any);
-    });
+    return TOTPValidator.validate("totp_token", jqueryMock.jquery as any);
+  });
 
-    it("should fail validating TOTP token", () => {
-        const errorMessage = "Error while validating TOTP token";
+  it("should fail validating TOTP token", () => {
+    const errorMessage = "Error while validating TOTP token";
 
-        const postPromise = JQueryMock.JQueryDeferredMock();
-        postPromise.fail.yields(undefined, errorMessage);
-        postPromise.done.returns(postPromise);
+    const postPromise = JQueryMock.JQueryDeferredMock();
+    postPromise.fail.yields(undefined, errorMessage);
+    postPromise.done.returns(postPromise);
 
-        const jqueryMock = JQueryMock.JQueryMock();
-        jqueryMock.jquery.ajax.returns(postPromise);
+    const jqueryMock = JQueryMock.JQueryMock();
+    jqueryMock.jquery.ajax.returns(postPromise);
 
-        return TOTPValidator.validate("totp_token", jqueryMock.jquery as any)
-            .then(function () {
-                return BluebirdPromise.reject(new Error("Registration successfully finished while it should have not."));
-            }, function (err: Error) {
-                Assert.equal(errorMessage, err.message);
-                return BluebirdPromise.resolve();
-            });
-    });
+    return TOTPValidator.validate("totp_token", jqueryMock.jquery as any)
+      .then(function () {
+        return BluebirdPromise.reject(new Error("Registration successfully finished while it should have not."));
+      }, function (err: Error) {
+        Assert.equal(errorMessage, err.message);
+        return BluebirdPromise.resolve();
+      });
+  });
 });
\ No newline at end of file
diff --git a/package.json b/package.json
index 5a3e0a067..2393c6655 100644
--- a/package.json
+++ b/package.json
@@ -66,8 +66,8 @@
     "@types/query-string": "^4.3.1",
     "@types/randomstring": "^1.1.5",
     "@types/redis": "^2.6.0",
-    "@types/request": "0.0.46",
-    "@types/request-promise": "^4.1.37",
+    "@types/request": "^2.0.5",
+    "@types/request-promise": "^4.1.38",
     "@types/selenium-webdriver": "^3.0.4",
     "@types/sinon": "^2.2.1",
     "@types/speakeasy": "^2.0.1",
@@ -96,7 +96,7 @@
     "power-assert": "^1.4.4",
     "proxyquire": "^1.8.0",
     "query-string": "^4.3.4",
-    "request": "^2.81.0",
+    "request": "^2.83.0",
     "request-promise": "^4.2.2",
     "selenium-webdriver": "^3.5.0",
     "should": "^11.1.1",
diff --git a/server/src/lib/ErrorReplies.ts b/server/src/lib/ErrorReplies.ts
index 6e40e8db7..cd6a4599e 100644
--- a/server/src/lib/ErrorReplies.ts
+++ b/server/src/lib/ErrorReplies.ts
@@ -3,12 +3,12 @@ import BluebirdPromise = require("bluebird");
 import { IRequestLogger } from "./logging/IRequestLogger";
 
 function replyWithError(req: express.Request, res: express.Response,
-  code: number, logger: IRequestLogger): (err: Error) => void {
+  code: number, logger: IRequestLogger, body?: Object): (err: Error) => void {
   return function (err: Error): void {
     logger.error(req, "Reply with error %d: %s", code, err.message);
     logger.debug(req, "%s", err.stack);
     res.status(code);
-    res.send();
+    res.send(body);
   };
 }
 
@@ -27,7 +27,7 @@ export function replyWithError403(req: express.Request,
   return replyWithError(req, res, 403, logger);
 }
 
-export function replyWithError500(req: express.Request,
-  res: express.Response, logger: IRequestLogger) {
-  return replyWithError(req, res, 500, logger);
+export function replyWithError200(req: express.Request,
+  res: express.Response, logger: IRequestLogger, message: string) {
+  return replyWithError(req, res, 200, logger, { error: message });
 }
\ No newline at end of file
diff --git a/server/src/lib/FirstFactorValidator.ts b/server/src/lib/FirstFactorValidator.ts
index 678dfde13..045d63f01 100644
--- a/server/src/lib/FirstFactorValidator.ts
+++ b/server/src/lib/FirstFactorValidator.ts
@@ -9,7 +9,9 @@ export function validate(req: express.Request): BluebirdPromise<void> {
   return AuthenticationSession.get(req)
     .then(function (authSession: AuthenticationSession.AuthenticationSession) {
       if (!authSession.userid || !authSession.first_factor)
-        return BluebirdPromise.reject(new Exceptions.FirstFactorValidationError("First factor has not been validated yet."));
+        return BluebirdPromise.reject(
+          new Exceptions.FirstFactorValidationError(
+            "First factor has not been validated yet."));
 
       return BluebirdPromise.resolve();
     });
diff --git a/server/src/lib/IdentityCheckMiddleware.ts b/server/src/lib/IdentityCheckMiddleware.ts
index ffe9292f5..362288dc3 100644
--- a/server/src/lib/IdentityCheckMiddleware.ts
+++ b/server/src/lib/IdentityCheckMiddleware.ts
@@ -28,8 +28,10 @@ export interface IdentityValidable {
   preValidationInit(req: express.Request): BluebirdPromise<Identity.Identity>;
   postValidationInit(req: express.Request): BluebirdPromise<void>;
 
-  preValidationResponse(req: express.Request, res: express.Response): void; // Serves a page after identity check request
-  postValidationResponse(req: express.Request, res: express.Response): void; // Serves the page if identity validated
+  // Serves a page after identity check request
+  preValidationResponse(req: express.Request, res: express.Response): void;
+  // Serves the page if identity validated
+  postValidationResponse(req: express.Request, res: express.Response): void;
   mailSubject(): string;
 }
 
@@ -50,7 +52,8 @@ function consumeToken(token: string, challenge: string, userDataStore: IUserData
   return userDataStore.consumeIdentityValidationToken(token, challenge);
 }
 
-export function register(app: express.Application, pre_validation_endpoint: string, post_validation_endpoint: string, handler: IdentityValidable) {
+export function register(app: express.Application, pre_validation_endpoint: string,
+  post_validation_endpoint: string, handler: IdentityValidable) {
   app.get(pre_validation_endpoint, get_start_validation(handler, post_validation_endpoint));
   app.get(post_validation_endpoint, get_finish_validation(handler));
 }
@@ -91,14 +94,13 @@ export function get_finish_validation(handler: IdentityValidable): express.Reque
         handler.postValidationResponse(req, res);
         return BluebirdPromise.resolve();
       })
-      .catch(Exceptions.FirstFactorValidationError, ErrorReplies.replyWithError401(req, res, logger))
-      .catch(Exceptions.AccessDeniedError, ErrorReplies.replyWithError403(req, res, logger))
-      .catch(ErrorReplies.replyWithError500(req, res, logger));
+      .catch(ErrorReplies.replyWithError401(req, res, logger));
   };
 }
 
 
-export function get_start_validation(handler: IdentityValidable, postValidationEndpoint: string): express.RequestHandler {
+export function get_start_validation(handler: IdentityValidable, postValidationEndpoint: string)
+  : express.RequestHandler {
   return function (req: express.Request, res: express.Response): BluebirdPromise<void> {
     const logger = ServerVariablesHandler.getLogger(req.app);
     const notifier = ServerVariablesHandler.getNotifier(req.app);
@@ -113,13 +115,15 @@ export function get_start_validation(handler: IdentityValidable, postValidationE
         logger.info(req, "Start identity validation of user \"%s\"", userid);
 
         if (!(email && userid))
-          return BluebirdPromise.reject(new Exceptions.IdentityError("Missing user id or email address"));
+          return BluebirdPromise.reject(new Exceptions.IdentityError(
+            "Missing user id or email address"));
 
         return createAndSaveToken(userid, handler.challenge(), userDataStore);
       })
       .then(function (token: string) {
         const host = req.get("Host");
-        const link_url = util.format("https://%s%s?identity_token=%s", host, postValidationEndpoint, token);
+        const link_url = util.format("https://%s%s?identity_token=%s", host,
+          postValidationEndpoint, token);
         logger.info(req, "Notification sent to user \"%s\"", identity.userid);
         return notifier.notify(identity, handler.mailSubject(), link_url);
       })
@@ -127,9 +131,6 @@ export function get_start_validation(handler: IdentityValidable, postValidationE
         handler.preValidationResponse(req, res);
         return BluebirdPromise.resolve();
       })
-      .catch(Exceptions.FirstFactorValidationError, ErrorReplies.replyWithError401(req, res, logger))
-      .catch(Exceptions.IdentityError, ErrorReplies.replyWithError400(req, res, logger))
-      .catch(Exceptions.AccessDeniedError, ErrorReplies.replyWithError403(req, res, logger))
-      .catch(ErrorReplies.replyWithError500(req, res, logger));
+      .catch(ErrorReplies.replyWithError401(req, res, logger));
   };
 }
diff --git a/server/src/lib/routes/FirstFactorBlocker.ts b/server/src/lib/routes/FirstFactorBlocker.ts
index 0cab96e9f..41b88240c 100644
--- a/server/src/lib/routes/FirstFactorBlocker.ts
+++ b/server/src/lib/routes/FirstFactorBlocker.ts
@@ -7,6 +7,7 @@ import ErrorReplies = require("../ErrorReplies");
 import objectPath = require("object-path");
 import { ServerVariablesHandler } from "../ServerVariablesHandler";
 import AuthenticationSession = require("../AuthenticationSession");
+import UserMessages = require("../../../../shared/UserMessages");
 
 type Handler = (req: express.Request, res: express.Response) => BluebirdPromise<void>;
 
@@ -21,6 +22,6 @@ export default function (callback: Handler): Handler {
       .then(function () {
         return callback(req, res);
       })
-      .catch(Exceptions.FirstFactorValidationError, ErrorReplies.replyWithError401(req, res, logger));
+      .catch(ErrorReplies.replyWithError401(req, res, logger));
   };
 }
\ No newline at end of file
diff --git a/server/src/lib/routes/firstfactor/post.ts b/server/src/lib/routes/firstfactor/post.ts
index b7ba04327..086700bbf 100644
--- a/server/src/lib/routes/firstfactor/post.ts
+++ b/server/src/lib/routes/firstfactor/post.ts
@@ -12,6 +12,7 @@ import { ServerVariablesHandler } from "../../ServerVariablesHandler";
 import AuthenticationSession = require("../../AuthenticationSession");
 import Constants = require("../../../../../shared/constants");
 import { DomainExtractor } from "../../utils/DomainExtractor";
+import UserMessages = require("../../../../../shared/UserMessages");
 
 export default function (req: express.Request, res: express.Response): BluebirdPromise<void> {
   const username: string = req.body.username;
@@ -22,9 +23,7 @@ export default function (req: express.Request, res: express.Response): BluebirdP
   const config = ServerVariablesHandler.getConfiguration(req.app);
 
   if (!username || !password) {
-    const err = new Error("No username or password");
-    ErrorReplies.replyWithError401(req, res, logger)(err);
-    return BluebirdPromise.reject(err);
+    return BluebirdPromise.reject(new Error("No username or password."));
   }
 
   const regulator = ServerVariablesHandler.getAuthenticationRegulator(req.app);
@@ -93,12 +92,9 @@ export default function (req: express.Request, res: express.Response): BluebirdP
       }
       return BluebirdPromise.resolve();
     })
-    .catch(exceptions.LdapSearchError, ErrorReplies.replyWithError500(req, res, logger))
     .catch(exceptions.LdapBindError, function (err: Error) {
       regulator.mark(username, false);
-      return ErrorReplies.replyWithError401(req, res, logger)(err);
+      return ErrorReplies.replyWithError200(req, res, logger, UserMessages.OPERATION_FAILED)(err);
     })
-    .catch(exceptions.AuthenticationRegulationError, ErrorReplies.replyWithError403(req, res, logger))
-    .catch(exceptions.DomainAccessDenied, ErrorReplies.replyWithError401(req, res, logger))
-    .catch(ErrorReplies.replyWithError500(req, res, logger));
+    .catch(ErrorReplies.replyWithError200(req, res, logger, UserMessages.OPERATION_FAILED));
 }
diff --git a/server/src/lib/routes/password-reset/form/post.ts b/server/src/lib/routes/password-reset/form/post.ts
index d84c4c863..15dba4be2 100644
--- a/server/src/lib/routes/password-reset/form/post.ts
+++ b/server/src/lib/routes/password-reset/form/post.ts
@@ -6,6 +6,7 @@ import exceptions = require("../../../Exceptions");
 import { ServerVariablesHandler } from "../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../AuthenticationSession");
 import ErrorReplies = require("../../../ErrorReplies");
+import UserMessages = require("../../../../../../shared/UserMessages");
 
 import Constants = require("./../constants");
 
@@ -23,8 +24,6 @@ export default function (req: express.Request, res: express.Response): BluebirdP
       logger.debug(req, "Challenge %s", authSession.identity_check.challenge);
 
       if (authSession.identity_check.challenge != Constants.CHALLENGE) {
-        res.status(403);
-        res.send();
         return BluebirdPromise.reject(new Error("Bad challenge."));
       }
       return ldapPasswordUpdater.updatePassword(authSession.identity_check.userid, newPassword);
@@ -37,5 +36,5 @@ export default function (req: express.Request, res: express.Response): BluebirdP
       res.send();
       return BluebirdPromise.resolve();
     })
-    .catch(ErrorReplies.replyWithError500(req, res, logger));
+    .catch(ErrorReplies.replyWithError200(req, res, logger, UserMessages.RESET_PASSWORD_FAILED));
 }
diff --git a/server/src/lib/routes/secondfactor/redirect.ts b/server/src/lib/routes/secondfactor/redirect.ts
index 4761f2a94..4f258e8ab 100644
--- a/server/src/lib/routes/secondfactor/redirect.ts
+++ b/server/src/lib/routes/secondfactor/redirect.ts
@@ -18,5 +18,6 @@ export default function (req: express.Request, res: express.Response): BluebirdP
             });
             return BluebirdPromise.resolve();
         })
-        .catch(ErrorReplies.replyWithError500(req, res, logger));
+        .catch(ErrorReplies.replyWithError200(req, res, logger,
+            "Unexpected error."));
 }
\ No newline at end of file
diff --git a/server/src/lib/routes/secondfactor/totp/identity/RegistrationHandler.ts b/server/src/lib/routes/secondfactor/totp/identity/RegistrationHandler.ts
index a395bf132..d289773fe 100644
--- a/server/src/lib/routes/secondfactor/totp/identity/RegistrationHandler.ts
+++ b/server/src/lib/routes/secondfactor/totp/identity/RegistrationHandler.ts
@@ -11,6 +11,7 @@ import Endpoints = require("../../../../../../../shared/api");
 import ErrorReplies = require("../../../../ErrorReplies");
 import { ServerVariablesHandler } from "../../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../../AuthenticationSession");
+import UserMessages = require("../../../../../../../shared/UserMessages");
 
 import FirstFactorValidator = require("../../../../FirstFactorValidator");
 
@@ -62,8 +63,6 @@ export default class RegistrationHandler implements IdentityValidable {
         const challenge = authSession.identity_check.challenge;
 
         if (challenge != Constants.CHALLENGE || !userid) {
-          res.status(403);
-          res.send();
           return BluebirdPromise.reject(new Error("Bad challenge."));
         }
 
@@ -83,7 +82,7 @@ export default class RegistrationHandler implements IdentityValidable {
             });
           });
       })
-      .catch(ErrorReplies.replyWithError500(req, res, logger));
+      .catch(ErrorReplies.replyWithError200(req, res, logger, UserMessages.OPERATION_FAILED));
   }
 
   mailSubject(): string {
diff --git a/server/src/lib/routes/secondfactor/totp/sign/post.ts b/server/src/lib/routes/secondfactor/totp/sign/post.ts
index 134de6533..d9b5afd9f 100644
--- a/server/src/lib/routes/secondfactor/totp/sign/post.ts
+++ b/server/src/lib/routes/secondfactor/totp/sign/post.ts
@@ -10,6 +10,7 @@ import redirect from "../../redirect";
 import ErrorReplies = require("../../../../ErrorReplies");
 import { ServerVariablesHandler } from "./../../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../../AuthenticationSession");
+import UserMessages = require("../../../../../../../shared/UserMessages");
 
 const UNAUTHORIZED_MESSAGE = "Unauthorized access";
 
@@ -25,7 +26,7 @@ export function handler(req: express.Request, res: express.Response): BluebirdPr
   return AuthenticationSession.get(req)
     .then(function (_authSession: AuthenticationSession.AuthenticationSession) {
       authSession = _authSession;
-      logger.info(req, "Initiate TOTP validation for user '%s'", authSession.userid);
+      logger.info(req, "Initiate TOTP validation for user '%s'.", authSession.userid);
       return userDataStore.retrieveTOTPSecret(authSession.userid);
     })
     .then(function (doc: TOTPSecretDocument) {
@@ -33,11 +34,11 @@ export function handler(req: express.Request, res: express.Response): BluebirdPr
       return totpValidator.validate(token, doc.secret.base32);
     })
     .then(function () {
-      logger.debug(req, "TOTP validation succeeded");
+      logger.debug(req, "TOTP validation succeeded.");
       authSession.second_factor = true;
       redirect(req, res);
       return BluebirdPromise.resolve();
     })
-    .catch(exceptions.InvalidTOTPError, ErrorReplies.replyWithError401(req, res, logger))
-    .catch(ErrorReplies.replyWithError500(req, res, logger));
+    .catch(ErrorReplies.replyWithError200(req, res, logger,
+      UserMessages.OPERATION_FAILED));
 }
diff --git a/server/src/lib/routes/secondfactor/u2f/register/post.ts b/server/src/lib/routes/secondfactor/u2f/register/post.ts
index 1a64ad64d..6d7e9d4b1 100644
--- a/server/src/lib/routes/secondfactor/u2f/register/post.ts
+++ b/server/src/lib/routes/secondfactor/u2f/register/post.ts
@@ -12,6 +12,7 @@ import redirect from "../../redirect";
 import ErrorReplies = require("../../../../ErrorReplies");
 import { ServerVariablesHandler } from "../../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../../AuthenticationSession");
+import UserMessages = require("../../../../../../../shared/UserMessages");
 
 
 export default FirstFactorBlocker(handler);
@@ -31,15 +32,11 @@ function handler(req: express.Request, res: express.Response): BluebirdPromise<v
       const registrationRequest = authSession.register_request;
 
       if (!registrationRequest) {
-        res.status(403);
-        res.send();
         return BluebirdPromise.reject(new Error("No registration request"));
       }
 
       if (!authSession.identity_check
         || authSession.identity_check.challenge != "u2f-register") {
-        res.status(403);
-        res.send();
         return BluebirdPromise.reject(new Error("Bad challenge for registration request"));
       }
 
@@ -67,5 +64,6 @@ function handler(req: express.Request, res: express.Response): BluebirdPromise<v
       redirect(req, res);
       return BluebirdPromise.resolve();
     })
-    .catch(ErrorReplies.replyWithError500(req, res, logger));
+    .catch(ErrorReplies.replyWithError200(req, res, logger,
+      UserMessages.OPERATION_FAILED));
 }
diff --git a/server/src/lib/routes/secondfactor/u2f/register_request/get.ts b/server/src/lib/routes/secondfactor/u2f/register_request/get.ts
index 7d1119c34..4c9a148cd 100644
--- a/server/src/lib/routes/secondfactor/u2f/register_request/get.ts
+++ b/server/src/lib/routes/secondfactor/u2f/register_request/get.ts
@@ -10,6 +10,7 @@ import FirstFactorBlocker from "../../../FirstFactorBlocker";
 import ErrorReplies = require("../../../../ErrorReplies");
 import {  ServerVariablesHandler } from "../../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../../AuthenticationSession");
+import UserMessages = require("../../../../../../../shared/UserMessages");
 
 export default FirstFactorBlocker(handler);
 
@@ -41,5 +42,6 @@ function handler(req: express.Request, res: express.Response): BluebirdPromise<v
             res.json(registrationRequest);
             return BluebirdPromise.resolve();
         })
-        .catch(ErrorReplies.replyWithError500(req, res, logger));
+        .catch(ErrorReplies.replyWithError200(req, res, logger,
+            UserMessages.OPERATION_FAILED));
 }
\ No newline at end of file
diff --git a/server/src/lib/routes/secondfactor/u2f/sign/post.ts b/server/src/lib/routes/secondfactor/u2f/sign/post.ts
index 1df8a184f..dfa9c38de 100644
--- a/server/src/lib/routes/secondfactor/u2f/sign/post.ts
+++ b/server/src/lib/routes/secondfactor/u2f/sign/post.ts
@@ -13,6 +13,7 @@ import redirect from "../../redirect";
 import ErrorReplies = require("../../../../ErrorReplies");
 import { ServerVariablesHandler } from "../../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../../AuthenticationSession");
+import UserMessages = require("../../../../../../../shared/UserMessages");
 
 export default FirstFactorBlocker(handler);
 
@@ -50,6 +51,7 @@ export function handler(req: express.Request, res: express.Response): BluebirdPr
       redirect(req, res);
       return BluebirdPromise.resolve();
     })
-    .catch(ErrorReplies.replyWithError500(req, res, logger));
+    .catch(ErrorReplies.replyWithError200(req, res, logger,
+      UserMessages.OPERATION_FAILED));
 }
 
diff --git a/server/src/lib/routes/secondfactor/u2f/sign_request/get.ts b/server/src/lib/routes/secondfactor/u2f/sign_request/get.ts
index af0ebf295..bdd40f44a 100644
--- a/server/src/lib/routes/secondfactor/u2f/sign_request/get.ts
+++ b/server/src/lib/routes/secondfactor/u2f/sign_request/get.ts
@@ -13,6 +13,7 @@ import FirstFactorBlocker from "../../../FirstFactorBlocker";
 import ErrorReplies = require("../../../../ErrorReplies");
 import { ServerVariablesHandler } from "../../../../ServerVariablesHandler";
 import AuthenticationSession = require("../../../../AuthenticationSession");
+import UserMessages = require("../../../../../../../shared/UserMessages");
 
 export default FirstFactorBlocker(handler);
 
@@ -50,7 +51,7 @@ export function handler(req: express.Request, res: express.Response): BluebirdPr
       res.json(authenticationMessage);
       return BluebirdPromise.resolve();
     })
-    .catch(exceptions.AccessDeniedError, ErrorReplies.replyWithError401(req, res, logger))
-    .catch(ErrorReplies.replyWithError500(req, res, logger));
+    .catch(ErrorReplies.replyWithError200(req, res, logger,
+      UserMessages.OPERATION_FAILED));
 }
 
diff --git a/server/src/lib/routes/verify/get.ts b/server/src/lib/routes/verify/get.ts
index fcbc73364..ccf21be0c 100644
--- a/server/src/lib/routes/verify/get.ts
+++ b/server/src/lib/routes/verify/get.ts
@@ -67,7 +67,10 @@ export default function (req: express.Request, res: express.Response): BluebirdP
       res.send();
       return BluebirdPromise.resolve();
     })
-    .catch(exceptions.DomainAccessDenied, ErrorReplies.replyWithError403(req, res, logger))
+    // The user is authenticated but has restricted access -> 403
+    .catch(exceptions.DomainAccessDenied, ErrorReplies
+      .replyWithError403(req, res, logger))
+    // The user is not yet authenticated -> 401
     .catch(ErrorReplies.replyWithError401(req, res, logger));
 }
 
diff --git a/server/src/views/layout/layout.pug b/server/src/views/layout/layout.pug
index 3f95cb9bc..24d96080a 100644
--- a/server/src/views/layout/layout.pug
+++ b/server/src/views/layout/layout.pug
@@ -5,7 +5,7 @@ html
         title Authelia - 2FA
         meta(name="viewport", content="width=device-width, initial-scale=1.0")/
         link(rel="icon", href="/img/icon.png" type="image/png" sizes="32x32")/
-        link(rel="stylesheet", type="text/css", href="/css/authelia.min.css")/
+        link(rel="stylesheet", type="text/css", href="/css/authelia.css")/
         if redirection_url
             <meta http-equiv="refresh" content="5;url=#{redirection_url}"> 
     body
diff --git a/server/test/IdentityCheckMiddleware.test.ts b/server/test/IdentityCheckMiddleware.test.ts
index 37388c3e6..62416179b 100644
--- a/server/test/IdentityCheckMiddleware.test.ts
+++ b/server/test/IdentityCheckMiddleware.test.ts
@@ -5,7 +5,7 @@ import AuthenticationSession = require("../src/lib/AuthenticationSession");
 import { UserDataStore } from "../src/lib/storage/UserDataStore";
 
 import exceptions = require("../src/lib/Exceptions");
-import assert = require("assert");
+import Assert = require("assert");
 import Promise = require("bluebird");
 import express = require("express");
 import BluebirdPromise = require("bluebird");
@@ -69,11 +69,11 @@ describe("test identity check process", function () {
       return callback(req as any, res as any, undefined)
         .then(function () { return BluebirdPromise.reject("Should fail"); })
         .catch(function () {
-          assert.equal(res.status.getCall(0).args[0], 401);
+          Assert.equal(res.status.getCall(0).args[0], 401);
         });
     });
 
-    it("should send 400 if email is missing in provided identity", function () {
+    it("should send 401 if email is missing in provided identity", function () {
       const identity = { userid: "abc" };
 
       identityValidable.preValidationInit.returns(BluebirdPromise.resolve(identity));
@@ -82,11 +82,11 @@ describe("test identity check process", function () {
       return callback(req as any, res as any, undefined)
         .then(function () { return BluebirdPromise.reject("Should fail"); })
         .catch(function () {
-          assert.equal(res.status.getCall(0).args[0], 400);
+          Assert.equal(res.status.getCall(0).args[0], 401);
         });
     });
 
-    it("should send 400 if userid is missing in provided identity", function () {
+    it("should send 401 if userid is missing in provided identity", function () {
       const endpoint = "/protected";
       const identity = { email: "abc@example.com" };
 
@@ -96,7 +96,7 @@ describe("test identity check process", function () {
       return callback(req as any, res as any, undefined)
         .then(function () { return BluebirdPromise.reject(new Error("It should fail")); })
         .catch(function (err: Error) {
-          assert.equal(res.status.getCall(0).args[0], 400);
+          Assert.equal(res.status.getCall(0).args[0], 401);
           return BluebirdPromise.resolve();
         });
     });
@@ -111,23 +111,23 @@ describe("test identity check process", function () {
 
       return callback(req as any, res as any, undefined)
         .then(function () {
-          assert(notifier.notify.calledOnce);
-          assert(mocks.userDataStore.produceIdentityValidationTokenStub.calledOnce);
-          assert.equal(mocks.userDataStore.produceIdentityValidationTokenStub.getCall(0).args[0], "user");
-          assert.equal(mocks.userDataStore.produceIdentityValidationTokenStub.getCall(0).args[3], 240000);
+          Assert(notifier.notify.calledOnce);
+          Assert(mocks.userDataStore.produceIdentityValidationTokenStub.calledOnce);
+          Assert.equal(mocks.userDataStore.produceIdentityValidationTokenStub.getCall(0).args[0], "user");
+          Assert.equal(mocks.userDataStore.produceIdentityValidationTokenStub.getCall(0).args[3], 240000);
         });
     });
   }
 
   function test_finish_get_handler() {
-    it("should send 403 if no identity_token is provided", function () {
+    it("should send 401 if no identity_token is provided", function () {
 
       const callback = IdentityValidator.get_finish_validation(identityValidable);
 
       return callback(req as any, res as any, undefined)
         .then(function () { return BluebirdPromise.reject("Should fail"); })
         .catch(function () {
-          assert.equal(res.status.getCall(0).args[0], 403);
+          Assert.equal(res.status.getCall(0).args[0], 401);
         });
     });
 
@@ -138,7 +138,7 @@ describe("test identity check process", function () {
       return callback(req as any, res as any, undefined);
     });
 
-    it("should return 500 if identity_token is provided but invalid", function () {
+    it("should return 401 if identity_token is provided but invalid", function () {
       req.query.identity_token = "token";
 
       mocks.userDataStore.consumeIdentityValidationTokenStub.returns(BluebirdPromise.reject(new Error("Invalid token")));
@@ -147,7 +147,7 @@ describe("test identity check process", function () {
       return callback(req as any, res as any, undefined)
         .then(function () { return BluebirdPromise.reject("Should fail"); })
         .catch(function () {
-          assert.equal(res.status.getCall(0).args[0], 500);
+          Assert.equal(res.status.getCall(0).args[0], 401);
         });
     });
 
@@ -165,7 +165,7 @@ describe("test identity check process", function () {
         })
         .then(function () { return BluebirdPromise.reject("Should fail"); })
         .catch(function () {
-          assert.equal(authSession.identity_check.userid, "user");
+          Assert.equal(authSession.identity_check.userid, "user");
           return BluebirdPromise.resolve();
         });
     });
diff --git a/server/test/routes/firstfactor/post.test.ts b/server/test/routes/firstfactor/post.test.ts
index 17b3548c9..89c1d72e8 100644
--- a/server/test/routes/firstfactor/post.test.ts
+++ b/server/test/routes/firstfactor/post.test.ts
@@ -1,7 +1,7 @@
 
 import sinon = require("sinon");
 import BluebirdPromise = require("bluebird");
-import assert = require("assert");
+import Assert = require("assert");
 import winston = require("winston");
 
 import FirstFactorPost = require("../../../src/lib/routes/firstfactor/post");
@@ -87,8 +87,8 @@ describe("test the first factor validation route", function () {
         return FirstFactorPost.default(req as any, res as any);
       })
       .then(function () {
-        assert.equal("username", authSession.userid);
-        assert(res.send.calledOnce);
+        Assert.equal("username", authSession.userid);
+        Assert(res.send.calledOnce);
       });
   });
 
@@ -113,27 +113,32 @@ describe("test the first factor validation route", function () {
         return FirstFactorPost.default(req as any, res as any);
       })
       .then(function () {
-        assert.equal("test_ok@example.com", authSession.email);
+        Assert.equal("test_ok@example.com", authSession.email);
       });
   });
 
-  it("should return status code 401 when LDAP authenticator throws", function () {
+  it("should return error message when LDAP authenticator throws", function () {
     (serverVariables.ldapAuthenticator as any).authenticate.withArgs("username", "password")
       .returns(BluebirdPromise.reject(new exceptions.LdapBindError("Bad credentials")));
     return FirstFactorPost.default(req as any, res as any)
       .then(function () {
-        assert.equal(401, res.status.getCall(0).args[0]);
-        assert.equal(regulator.mark.getCall(0).args[0], "username");
+        Assert.equal(res.status.getCall(0).args[0], 200);
+        Assert.equal(regulator.mark.getCall(0).args[0], "username");
+        Assert.deepEqual(res.send.getCall(0).args[0], {
+          error: "Operation failed."
+        });
       });
   });
 
-  it("should return status code 403 when regulator rejects authentication", function () {
+  it("should return error message when regulator rejects authentication", function () {
     const err = new exceptions.AuthenticationRegulationError("Authentication regulation...");
     regulator.regulate.returns(BluebirdPromise.reject(err));
     return FirstFactorPost.default(req as any, res as any)
       .then(function () {
-        assert.equal(403, res.status.getCall(0).args[0]);
-        assert.equal(1, res.send.callCount);
+        Assert.equal(res.status.getCall(0).args[0], 200);
+        Assert.deepEqual(res.send.getCall(0).args[0], {
+          error: "Operation failed."
+        });
       });
   });
 });
diff --git a/server/test/routes/password-reset/post.test.ts b/server/test/routes/password-reset/post.test.ts
index 86fda49cd..436715ad0 100644
--- a/server/test/routes/password-reset/post.test.ts
+++ b/server/test/routes/password-reset/post.test.ts
@@ -6,7 +6,7 @@ import { ServerVariablesHandler } from "../../../src/lib/ServerVariablesHandler"
 import { UserDataStore } from "../../../src/lib/storage/UserDataStore";
 import Sinon = require("sinon");
 import winston = require("winston");
-import assert = require("assert");
+import Assert = require("assert");
 import BluebirdPromise = require("bluebird");
 
 import ExpressMock = require("../../mocks/express");
@@ -85,9 +85,9 @@ describe("test reset password route", function () {
         .then(function () {
           return AuthenticationSession.get(req as any);
         }).then(function (_authSession: AuthenticationSession.AuthenticationSession) {
-          assert.equal(res.status.getCall(0).args[0], 204);
-          assert.equal(_authSession.first_factor, false);
-          assert.equal(_authSession.second_factor, false);
+          Assert.equal(res.status.getCall(0).args[0], 204);
+          Assert.equal(_authSession.first_factor, false);
+          Assert.equal(_authSession.second_factor, false);
           return BluebirdPromise.resolve();
         });
     });
@@ -102,7 +102,10 @@ describe("test reset password route", function () {
           return PasswordResetFormPost.default(req as any, res as any);
         })
         .then(function () {
-          assert.equal(res.status.getCall(0).args[0], 403);
+          Assert.equal(res.status.getCall(0).args[0], 200);
+          Assert.deepEqual(res.send.getCall(0).args[0], {
+            error: "An error occurred during password reset. Your password has not been changed."
+          });
         });
     });
 
@@ -121,7 +124,10 @@ describe("test reset password route", function () {
           };
           return PasswordResetFormPost.default(req as any, res as any);
         }).then(function () {
-          assert.equal(res.status.getCall(0).args[0], 500);
+          Assert.equal(res.status.getCall(0).args[0], 200);
+          Assert.deepEqual(res.send.getCall(0).args[0], {
+            error: "An error occurred during password reset. Your password has not been changed."
+          });
           return BluebirdPromise.resolve();
         });
     });
diff --git a/server/test/routes/secondfactor/u2f/register/post.test.ts b/server/test/routes/secondfactor/u2f/register/post.test.ts
index 601e7f099..86d0cd01d 100644
--- a/server/test/routes/secondfactor/u2f/register/post.test.ts
+++ b/server/test/routes/secondfactor/u2f/register/post.test.ts
@@ -84,7 +84,7 @@ describe("test u2f routes: register", function () {
         });
     });
 
-    it("should return unauthorized on finishRegistration error", function () {
+    it("should return error message on finishRegistration error", function () {
       const user_key_container = {};
       const u2f_mock = U2FMock.U2FMock();
       u2f_mock.checkRegistration.returns({ errorCode: 500 });
@@ -103,12 +103,15 @@ describe("test u2f routes: register", function () {
         })
         .then(function () { return BluebirdPromise.reject(new Error("It should fail")); })
         .catch(function () {
-          assert.equal(500, res.status.getCall(0).args[0]);
+          assert.equal(200, res.status.getCall(0).args[0]);
+          assert.deepEqual(res.send.getCall(0).args[0], {
+            error: "Operation failed."
+          });
           return BluebirdPromise.resolve();
         });
     });
 
-    it("should return 403 when register_request is not provided", function () {
+    it("should return error message when register_request is not provided", function () {
       const user_key_container = {};
       const u2f_mock = U2FMock.U2FMock();
       u2f_mock.checkRegistration.returns(BluebirdPromise.resolve());
@@ -121,12 +124,15 @@ describe("test u2f routes: register", function () {
         })
         .then(function () { return BluebirdPromise.reject(new Error("It should fail")); })
         .catch(function () {
-          assert.equal(403, res.status.getCall(0).args[0]);
+          assert.equal(200, res.status.getCall(0).args[0]);
+          assert.deepEqual(res.send.getCall(0).args[0], {
+            error: "Operation failed."
+          });
           return BluebirdPromise.resolve();
         });
     });
 
-    it("should return forbidden error when no auth request has been initiated", function () {
+    it("should return error message when no auth request has been initiated", function () {
       const user_key_container = {};
       const u2f_mock = U2FMock.U2FMock();
       u2f_mock.checkRegistration.returns(BluebirdPromise.resolve());
@@ -139,12 +145,15 @@ describe("test u2f routes: register", function () {
         })
         .then(function () { return BluebirdPromise.reject(new Error("It should fail")); })
         .catch(function () {
-          assert.equal(403, res.status.getCall(0).args[0]);
+          assert.equal(200, res.status.getCall(0).args[0]);
+          assert.deepEqual(res.send.getCall(0).args[0], {
+            error: "Operation failed."
+          });
           return BluebirdPromise.resolve();
         });
     });
 
-    it("should return forbidden error when identity has not been verified", function () {
+    it("should return error message when identity has not been verified", function () {
       return AuthenticationSession.get(req as any)
         .then(function (authSession) {
           authSession.identity_check = undefined;
@@ -152,7 +161,10 @@ describe("test u2f routes: register", function () {
         })
         .then(function () { return BluebirdPromise.reject(new Error("It should fail")); })
         .catch(function () {
-          assert.equal(403, res.status.getCall(0).args[0]);
+          assert.equal(200, res.status.getCall(0).args[0]);
+          assert.deepEqual(res.send.getCall(0).args[0], {
+            error: "Operation failed."
+          });
           return BluebirdPromise.resolve();
         });
     });
diff --git a/server/test/routes/secondfactor/u2f/register_request/get.test.ts b/server/test/routes/secondfactor/u2f/register_request/get.test.ts
index 7465beb1e..168dca30d 100644
--- a/server/test/routes/secondfactor/u2f/register_request/get.test.ts
+++ b/server/test/routes/secondfactor/u2f/register_request/get.test.ts
@@ -1,7 +1,7 @@
 
 import sinon = require("sinon");
 import BluebirdPromise = require("bluebird");
-import assert = require("assert");
+import Assert = require("assert");
 import U2FRegisterRequestGet = require("../../../../../src/lib/routes/secondfactor/u2f/register_request/get");
 import AuthenticationSession = require("../../../../../src/lib/AuthenticationSession");
 import { ServerVariablesHandler } from "../../../../../src/lib/ServerVariablesHandler";
@@ -67,28 +67,31 @@ describe("test u2f routes: register_request", function () {
       mocks.u2f = u2f_mock;
       return U2FRegisterRequestGet.default(req as any, res as any)
         .then(function () {
-          assert.deepEqual(expectedRequest, res.json.getCall(0).args[0]);
+          Assert.deepEqual(expectedRequest, res.json.getCall(0).args[0]);
         });
     });
 
-    it("should return internal error on registration request", function (done) {
-      res.send = sinon.spy(function (data: any) {
-        assert.equal(500, res.status.getCall(0).args[0]);
-        done();
-      });
+    it("should return internal error on registration request", function () {
+      res.send = sinon.spy();
       const user_key_container = {};
       const u2f_mock = U2FMock.U2FMock();
       u2f_mock.request.returns(BluebirdPromise.reject("Internal error"));
 
       mocks.u2f = u2f_mock;
-      U2FRegisterRequestGet.default(req as any, res as any);
+      return U2FRegisterRequestGet.default(req as any, res as any)
+      .then(function() {
+        Assert.equal(res.status.getCall(0).args[0], 200);
+        Assert.deepEqual(res.send.getCall(0).args[0], {
+          error: "Operation failed."
+        });
+      });
     });
 
     it("should return forbidden if identity has not been verified", function () {
       authSession.identity_check = undefined;
       return U2FRegisterRequestGet.default(req as any, res as any)
         .then(function () {
-          assert.equal(403, res.status.getCall(0).args[0]);
+          Assert.equal(403, res.status.getCall(0).args[0]);
         });
     });
   });
diff --git a/server/test/routes/secondfactor/u2f/sign/post.test.ts b/server/test/routes/secondfactor/u2f/sign/post.test.ts
index 80d7394ea..aef978bbc 100644
--- a/server/test/routes/secondfactor/u2f/sign/post.test.ts
+++ b/server/test/routes/secondfactor/u2f/sign/post.test.ts
@@ -97,7 +97,9 @@ describe("test u2f routes: sign", function () {
     mocks.u2f = u2f_mock;
     return U2FSignPost.default(req as any, res as any)
       .then(function () {
-        Assert.equal(500, res.status.getCall(0).args[0]);
+        Assert.equal(res.status.getCall(0).args[0], 200);
+        Assert.deepEqual(res.send.getCall(0).args[0],
+          { error: "Operation failed." });
       });
   });
 });
diff --git a/server/test/server/PrivatePages.ts b/server/test/server/PrivatePages.ts
index 09bdb383b..cb2d8372b 100644
--- a/server/test/server/PrivatePages.ts
+++ b/server/test/server/PrivatePages.ts
@@ -127,25 +127,18 @@ describe("Private pages of the server must not be accessible without session", f
   });
 
   describe("Second factor endpoints must be protected if first factor is not validated", function () {
-    function should_post_and_reply_with(url: string, status_code: number): BluebirdPromise<void> {
-      return requestp.postAsync(url).then(function (response: request.RequestResponse) {
-        Assert.equal(response.statusCode, status_code);
-        return BluebirdPromise.resolve();
-      });
-    }
-
-    function should_get_and_reply_with(url: string, status_code: number): BluebirdPromise<void> {
-      return requestp.getAsync(url).then(function (response: request.RequestResponse) {
-        Assert.equal(response.statusCode, status_code);
-        return BluebirdPromise.resolve();
-      });
-    }
-
     function should_post_and_reply_with_401(url: string): BluebirdPromise<void> {
-      return should_post_and_reply_with(url, 401);
+      return requestp.postAsync(url).then(function (response: request.RequestResponse) {
+        Assert.equal(response.statusCode, 401);
+        return BluebirdPromise.resolve();
+      });
     }
+
     function should_get_and_reply_with_401(url: string): BluebirdPromise<void> {
-      return should_get_and_reply_with(url, 401);
+      return requestp.getAsync(url).then(function (response: request.RequestResponse) {
+        Assert.equal(response.statusCode, 401);
+        return BluebirdPromise.resolve();
+      });
     }
 
     it("should block " + Endpoints.SECOND_FACTOR_GET, function () {
diff --git a/shared/UserMessages.ts b/shared/UserMessages.ts
new file mode 100644
index 000000000..40640b1d6
--- /dev/null
+++ b/shared/UserMessages.ts
@@ -0,0 +1,23 @@
+
+export const AUTHENTICATION_FAILED = "Authentication failed. Please check your credentials.";
+export const AUTHENTICATION_SUCCEEDED = "Authentication succeeded. You can now access your services.";
+
+export const AUTHENTICATION_U2F_FAILED = "Authentication failed. Have you already registered your device?";
+export const AUTHENTICATION_TOTP_FAILED = "Authentication failed. Have you already registered your secret?";
+
+export const U2F_TRANSACTION_FINISH_FAILED = "U2F validation failed unexpectedly.";
+export const PLEASE_TOUCH_TOKEN = "Please touch the token on your U2F device.";
+
+export const REGISTRATION_U2F_FAILED = "Registration of U2F device failed.";
+
+export const DIFFERENT_PASSWORDS = "The passwords are different.";
+export const MISSING_PASSWORD = "You must enter your password twice.";
+export const RESET_PASSWORD_FAILED = "An error occurred during password reset. Your password has not been changed.";
+
+// Password reset request
+export const MISSING_USERNAME = "You must provide your username to reset your password.";
+export const MAIL_SENT = "An email has been sent to you. Follow the link to change your password.";
+export const MAIL_NOT_SENT = "The email cannot be sent. Please retry in few minutes.";
+
+export const UNAUTHORIZED_OPERATION = "You are not allowed to perform this operation.";
+export const OPERATION_FAILED = "Operation failed.";
\ No newline at end of file
diff --git a/test/features/authentication.feature b/test/features/authentication.feature
index 69ea88843..11a600fcb 100644
--- a/test/features/authentication.feature
+++ b/test/features/authentication.feature
@@ -12,7 +12,7 @@ Feature: Authentication scenarii
     When I set field "username" to "john"
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    Then I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    Then I get a notification of type "error" with message "Authentication failed. Please check your credentials."
 
   Scenario: User registers TOTP secret and succeeds authentication
     Given I visit "https://auth.test.local:8080/"
@@ -31,7 +31,7 @@ Feature: Authentication scenarii
     And I login with user "john" and password "password"
     And I use "BADTOKEN" as TOTP token
     And I click on "TOTP"
-    Then I get a notification of type "error" with message "Problem with TOTP validation."
+    Then I get a notification of type "error" with message "Authentication failed. Have you already registered your secret?"
 
   Scenario: Logout redirects user to redirect URL given in parameter
     When I visit "https://auth.test.local:8080/logout?redirect=https://home.test.local:8080/"
diff --git a/test/features/regulation.feature b/test/features/regulation.feature
index f361c2dd5..69e5a69ba 100644
--- a/test/features/regulation.feature
+++ b/test/features/regulation.feature
@@ -7,16 +7,16 @@ Feature: Authelia regulates authentication to avoid brute force
     And I set field "username" to "blackhat"
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    And I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    And I get a notification of type "error" with message "Authentication failed. Please check your credentials."
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    And I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    And I get a notification of type "error" with message "Authentication failed. Please check your credentials."
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    And I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    And I get a notification of type "error" with message "Authentication failed. Please check your credentials."
     When I set field "password" to "password"
     And I click on "Sign in"
-    Then I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    Then I get a notification of type "error" with message "Authentication failed. Please check your credentials."
 
   @needs-test-config
   @need-registered-user-blackhat
@@ -25,13 +25,13 @@ Feature: Authelia regulates authentication to avoid brute force
     And I set field "username" to "blackhat"
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    And I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    And I get a notification of type "error" with message "Authentication failed. Please check your credentials."
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    And I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    And I get a notification of type "error" with message "Authentication failed. Please check your credentials."
     And I set field "password" to "bad-password"
     And I click on "Sign in"
-    And I get a notification of type "error" with message "Authentication failed. Please double check your credentials."
+    And I get a notification of type "error" with message "Authentication failed. Please check your credentials."
     When I wait 6 seconds 
     And I set field "password" to "password"
     And I click on "Sign in"
diff --git a/test/features/reset-password.feature b/test/features/reset-password.feature
index c386f28c7..ba893f655 100644
--- a/test/features/reset-password.feature
+++ b/test/features/reset-password.feature
@@ -11,6 +11,12 @@ Feature: User is able to reset his password
     And I click on "Reset Password"
     Then I get a notification of type "success" with message "An email has been sent to you. Follow the link to change your password."
 
+  Scenario: Request password for unexisting user should behave like existing user
+    Given I'm on https://auth.test.local:8080/password-reset/request
+    When I set field "username" to "fake_user"
+    And I click on "Reset Password"
+    Then I get a notification of type "success" with message "An email has been sent to you. Follow the link to change your password."
+
   Scenario: User resets his password
     Given I'm on https://auth.test.local:8080/password-reset/request
     And I set field "username" to "james"
diff --git a/test/features/restrictions.feature b/test/features/restrictions.feature
index c2cf9889d..e331482b9 100644
--- a/test/features/restrictions.feature
+++ b/test/features/restrictions.feature
@@ -9,8 +9,8 @@ Feature: Non authenticated users have no access to certain pages
       | https://auth.test.local:8080/secondfactor                      | 401        |
       | https://auth.test.local:8080/verify                            | 401        |
       | https://auth.test.local:8080/secondfactor/u2f/identity/start   | 401        |
-      | https://auth.test.local:8080/secondfactor/u2f/identity/finish  | 403        |
+      | https://auth.test.local:8080/secondfactor/u2f/identity/finish  | 401        |
       | https://auth.test.local:8080/secondfactor/totp/identity/start  | 401        |
-      | https://auth.test.local:8080/secondfactor/totp/identity/finish | 403        |
-      | https://auth.test.local:8080/password-reset/identity/start     | 403        |
-      | https://auth.test.local:8080/password-reset/identity/finish    | 403        |
\ No newline at end of file
+      | https://auth.test.local:8080/secondfactor/totp/identity/finish | 401        |
+      | https://auth.test.local:8080/password-reset/identity/start     | 401        |
+      | https://auth.test.local:8080/password-reset/identity/finish    | 401        |
\ No newline at end of file