diff --git a/assets/js/src/ajax.js b/assets/js/src/ajax.js
index 3878a3582a..c44a1bf10b 100644
--- a/assets/js/src/ajax.js
+++ b/assets/js/src/ajax.js
@@ -60,7 +60,13 @@ define('ajax', ['mailpoet', 'jquery', 'underscore'], function(MailPoet, jQuery,
         ).then(function(data) {
           return data;
         }, function(xhr) {
-          return xhr.responseJSON;
+          if (!xhr.responseJSON) {
+            return {
+              errors: [{ error: 'undefined', message: "An unknown error occurred." }]
+            };
+          } else {
+            return xhr.responseJSON;
+          }
         });
 
         // clear options
diff --git a/lib/API/Endpoints/Settings.php b/lib/API/Endpoints/Settings.php
index ec3228ac34..dcf664e93e 100644
--- a/lib/API/Endpoints/Settings.php
+++ b/lib/API/Endpoints/Settings.php
@@ -21,7 +21,7 @@ class Settings extends APIEndpoint {
       foreach($settings as $name => $value) {
         Setting::setValue($name, $value);
       }
-      return $this->successResponse(Setting::getAll());
+      return $this->successResponse();
     }
   }
 }
diff --git a/lib/API/Endpoints/Setup.php b/lib/API/Endpoints/Setup.php
index b7a4929f77..90651784c0 100644
--- a/lib/API/Endpoints/Setup.php
+++ b/lib/API/Endpoints/Setup.php
@@ -1,10 +1,11 @@
 <?php
 namespace MailPoet\API\Endpoints;
+use \MailPoet\API\Endpoint as APIEndpoint;
 use \MailPoet\Config\Activator;
 
 if(!defined('ABSPATH')) exit;
 
-class Setup {
+class Setup extends APIEndpoint {
   function __construct() {
   }
 
@@ -13,12 +14,11 @@ class Setup {
       $activator = new Activator();
       $activator->deactivate();
       $activator->activate();
-      $result = true;
+      return $this->successResponse();
     } catch(\Exception $e) {
-      $result = false;
+      return $this->errorResponse(array(
+        $e->getMessage()
+      ));
     }
-    return array(
-      'result' => $result
-    );
   }
 }
diff --git a/tests/unit/API/SetupTest.php b/tests/unit/API/SetupTest.php
index fe44d2f3d8..9b45ca14c3 100644
--- a/tests/unit/API/SetupTest.php
+++ b/tests/unit/API/SetupTest.php
@@ -1,4 +1,5 @@
 <?php
+use \MailPoet\API\Response;
 use \MailPoet\API\Endpoints\Setup;
 use \MailPoet\Models\Setting;
 
@@ -8,12 +9,12 @@ class SetupTest extends MailPoetTest {
   }
 
   function testItCanReinstall() {
-    /*$router = new Setup();
+    $router = new Setup();
     $response = $router->reset();
-    expect($response['result'])->true();
+    expect($response->status)->equals(Response::STATUS_OK);
 
     $signup_confirmation = Setting::getValue('signup_confirmation.enabled');
-    expect($signup_confirmation)->true();*/
+    expect($signup_confirmation)->true();
   }
 
   function _after() {
diff --git a/views/settings.html b/views/settings.html
index 09b8bc0ddf..0f248f1003 100644
--- a/views/settings.html
+++ b/views/settings.html
@@ -77,20 +77,20 @@
             endpoint: 'settings',
             action: 'set',
             data: settings_data
+          }).always(function() {
+            MailPoet.Modal.loading(false);
           }).done(function(response) {
             MailPoet.Notice.success(
               "<%= __('Settings saved') %>",
               { scroll: true }
             );
-            MailPoet.Modal.loading(false);
           }).fail(function(response) {
-            if (response.errors !== undefined) {
+            if (response.errors.length > 0) {
               MailPoet.Notice.error(
                 response.errors.map(function(error) { return error.message; }),
                 { scroll: true }
               );
             }
-            MailPoet.Modal.loading(false);
           });
         }
 
diff --git a/views/settings/advanced.html b/views/settings/advanced.html
index 29a37f27f4..6e1e555f11 100644
--- a/views/settings/advanced.html
+++ b/views/settings/advanced.html
@@ -175,13 +175,16 @@
           MailPoet.Ajax.post({
             'endpoint': 'setup',
             'action': 'reset'
+          }).always(function() {
+            MailPoet.Modal.loading(false);
           }).done(function(response) {
-            if(response.result === true) {
-              window.location = "<%= admin_url('admin.php?page=mailpoet-newsletters') %>";
-            } else {
+            window.location = "<%= admin_url('admin.php?page=mailpoet-newsletters') %>";
+          }).fail(function(response) {
+            if (response.errors.length > 0) {
               MailPoet.Notice.error(
-                "<%= __('MailPoet could not be reinstalled. You may need to remove it manually first.') %>",
-              { scroll: true });
+                response.errors.map(function(error) { return error.message; }),
+                { scroll: true }
+              );
             }
           });
         }