diff --git a/app/js/controllers.js b/app/js/controllers.js
index a29a2625..84bd2f9b 100644
--- a/app/js/controllers.js
+++ b/app/js/controllers.js
@@ -155,6 +155,15 @@ angular.module('myApp.controllers', [])
         }, function (error) {
           $scope.progress.enabled = false;
           switch (error.type) {
+            case 'NETWORK_BAD_REQUEST':
+              if (location.protocol == 'https:') {
+                ErrorService.confirm({type: 'HTTPS_MIXED_FAIL'}).then(function () {
+                  location = location.toString().replace('/^https:/', 'http:');
+                });
+                error.handled = true;
+              }
+              break;
+
             case 'PHONE_NUMBER_INVALID':
               $scope.error = {field: 'phone'};
               error.handled = true;
@@ -282,7 +291,7 @@ angular.module('myApp.controllers', [])
     }
   })
 
-  .controller('AppImDialogsController', function ($scope, $location, MtpApiManager, AppUsersManager, AppChatsManager, AppMessagesManager, AppPeersManager) {
+  .controller('AppImDialogsController', function ($scope, $location, MtpApiManager, AppUsersManager, AppChatsManager, AppMessagesManager, AppPeersManager, ErrorService) {
 
     // console.log('init controller');
 
@@ -374,6 +383,15 @@ angular.module('myApp.controllers', [])
         }
 
       }, function (error) {
+        if (error.type == 'NETWORK_BAD_REQUEST') {
+          if (location.protocol == 'https:') {
+            ErrorService.confirm({type: 'HTTPS_MIXED_FAIL'}).then(function () {
+              location = location.toString().replace('/^https:/', 'http:');
+            });
+            error.handled = true;
+          }
+        }
+
         if (error.code == 401) {
           MtpApiManager.logOut()['finally'](function () {
             $location.url('/login');
diff --git a/app/js/lib/mtproto.js b/app/js/lib/mtproto.js
index 2cf91869..7c6a68a0 100644
--- a/app/js/lib/mtproto.js
+++ b/app/js/lib/mtproto.js
@@ -1196,14 +1196,25 @@ factory('MtpAuthorizer', function (MtpDcConfigurator, MtpRsaKeysManager, MtpSecu
       transformResponse: function (responseBuffer) {
         var deserializer = new TLDeserialization(responseBuffer, {mtproto: true});
 
-        var auth_key_id = deserializer.fetchLong('auth_key_id');
-        var msg_id      = deserializer.fetchLong('msg_id');
-        var msg_len     = deserializer.fetchInt('msg_len');
+        try {
+
+          var auth_key_id = deserializer.fetchLong('auth_key_id');
+          var msg_id      = deserializer.fetchLong('msg_id');
+          var msg_len     = deserializer.fetchInt('msg_len');
+
+        } catch (e) {
+          return $q.reject({code: 406, type: 'NETWORK_BAD_RESPONSE', problem: e.message, stack: e.stack});
+        }
 
         rng_seed_time();
 
         return deserializer;
       }
+    })['catch'](function (error) {
+      if (!error.message && !error.type) {
+        error = {code: 406, type: 'NETWORK_BAD_REQUEST'};
+      }
+      return $q.reject(error);
     });
   };
 
@@ -2189,6 +2200,11 @@ factory('MtpNetworkerFactory', function (MtpDcConfigurator, MtpMessageIdGenerato
       return $http.post('http://' + MtpDcConfigurator.chooseServer(self.dcID) + '/apiw1', resultArray, {
         responseType: 'arraybuffer',
         transformRequest: null
+      })['catch'](function (error) {
+        if (!error.message && !error.type) {
+          error = {code: 406, type: 'NETWORK_BAD_REQUEST'};
+        }
+        return $q.reject(error);
       });
     });
   };
diff --git a/app/partials/confirm_modal.html b/app/partials/confirm_modal.html
index b9c21dee..3a6efff9 100644
--- a/app/partials/confirm_modal.html
+++ b/app/partials/confirm_modal.html
@@ -9,6 +9,11 @@
       <span ng-switch-when="WEBOGRAM_UPDATED_RELOAD">A new version of Webogram is available. Load it?</span>
       <span ng-switch-when="HISTORY_FLUSH">Are you sure? This can not be undone!</span>
       <span ng-switch-when="TERMINATE_SESSIONS">Are you sure you want to log out all devices except for the current one?</span>
+      <span ng-switch-when="HTTPS_MIXED_FAIL">
+        Your browser does not support mixed content which is neccessary for MTProto support on https. <a href="https://github.com/zhukov/webogram/issues/237" target="_blank">Learn more &rarr;</a><br/>
+        Would you like use http-version instead?
+      </span>
+
       <span ng-switch-when="FILES_CLIPBOARD_PASTE">
         <ng-pluralize count="files.length"
                      when="{'one': 'Are you sure to send file from clipboard?', 'other': 'Are you sure to send {} files from clipboard?'}">
diff --git a/app/partials/error_modal.html b/app/partials/error_modal.html
index 3ff695bf..51fdd734 100644
--- a/app/partials/error_modal.html
+++ b/app/partials/error_modal.html
@@ -10,6 +10,7 @@
         <span ng-switch-when="401">Unauthorized</span>
         <span ng-switch-when="403">Access denied</span>
         <span ng-switch-when="404">Not found</span>
+        <span ng-switch-when="406">Network error</span>
         <span ng-switch-when="420">Too fast</span>
         <span ng-switch-default>Server error</span>
       </span>
@@ -20,6 +21,12 @@
   <div class="modal-body">
 
     <div ng-if="error" class="error_modal_description" ng-switch="error.type">
+      <span ng-switch-when="NETWORK_BAD_REQUEST">
+        Please check your internet connection.
+      </span>
+      <span ng-switch-when="NETWORK_BAD_RESPONSE">
+        Please check your internet connection.
+      </span>
       <span ng-switch-when="FIRSTNAME_INVALID">
         The first name you entered is invalid.
       </span>