diff --git a/lib/API/Endpoints/Mailer.php b/lib/API/Endpoints/Mailer.php
index 4ff8f0c158..2b71688c05 100644
--- a/lib/API/Endpoints/Mailer.php
+++ b/lib/API/Endpoints/Mailer.php
@@ -1,11 +1,12 @@
 <?php
 namespace MailPoet\API\Endpoints;
+use MailPoet\API\Endpoint as APIEndpoint;
+use MailPoet\API\Error as APIError;
 
 if(!defined('ABSPATH')) exit;
 
-class Mailer {
-  function send($data) {
-    $response = array();
+class Mailer extends APIEndpoint {
+  function send($data = array()) {
     try {
       $mailer = new \MailPoet\Mailer\Mailer(
         (isset($data['mailer'])) ? $data['mailer'] : false,
@@ -14,10 +15,17 @@ class Mailer {
       );
       $result = $mailer->send($data['newsletter'], $data['subscriber']);
     } catch(\Exception $e) {
-      $result = false;
-      $response['errors'] = array($e->getMessage());
+      return $this->errorResponse(array(
+        $e->getCode() => $e->getMessage()
+      ));
+    }
+
+    if($result === false) {
+      return $this->errorResponse(array(
+        APIError::BAD_REQUEST => __("The email could not be sent. Please check your settings.")
+      ));
+    } else {
+      return $this->successResponse(null);
     }
-    $response['result'] = ($result) ? true : false;
-    return $response;
   }
 }
\ No newline at end of file
diff --git a/lib/API/Response.php b/lib/API/Response.php
index acbc927e2f..96c6aaeff9 100644
--- a/lib/API/Response.php
+++ b/lib/API/Response.php
@@ -27,7 +27,7 @@ abstract class Response {
     if(!empty($this->meta)) {
       $response['meta'] = $this->meta;
     }
-    if(!empty($data)) {
+    if($data !== null) {
       $response = array_merge($response, $data);
     }
 
diff --git a/lib/API/SuccessResponse.php b/lib/API/SuccessResponse.php
index 35c2134741..d3be62ae00 100644
--- a/lib/API/SuccessResponse.php
+++ b/lib/API/SuccessResponse.php
@@ -6,12 +6,14 @@ if(!defined('ABSPATH')) exit;
 class SuccessResponse extends Response {
   public $data;
 
-  function __construct($data = array(), $meta = array(), $status = self::STATUS_OK) {
+  function __construct($data = null, $meta = null, $status = self::STATUS_OK) {
     parent::__construct($status, $meta);
     $this->data = $data;
   }
 
   function getData() {
+    if($this->data === null) return null;
+
     return array(
       'data' => $this->data
     );
diff --git a/views/settings/mta.html b/views/settings/mta.html
index 540dd40a61..e0c2f6092b 100644
--- a/views/settings/mta.html
+++ b/views/settings/mta.html
@@ -699,36 +699,20 @@
               email: recipient
             }
           }
-        }).done(function(response) {
+        }).always(function() {
           MailPoet.Modal.loading(false);
-          if(response.result === true) {
-            MailPoet.Notice.success(
-              "<%= __('The email has been sent! Check your inbox.') %>",
+        }).done(function(response) {
+          MailPoet.Notice.success(
+            "<%= __('The email has been sent! Check your inbox.') %>",
+            { scroll: true }
+          );
+        }).fail(function(response) {
+          if (response.errors.length > 0) {
+            MailPoet.Notice.error(
+              response.errors.map(function(error) { return error.message; }),
               { scroll: true }
             );
-          } else {
-            if (response.errors) {
-              MailPoet.Notice.error(
-                "<%= __('The email could not be sent: ') %> " + response.errors,
-                { scroll: true }
-              );
-            }
-            else {
-              if(mailer.method === 'PHPMail') {
-                MailPoet.Notice.error(
-                  "<%= __('The email could not be sent. Please contact your host to fix this issue.') %>",
-                  { scroll: true, static: true }
-                );
-              } else {
-                MailPoet.Notice.error(
-                  "<%= __('The email could not be sent. Please check your settings.') %>",
-                  { scroll: true }
-                );
-              }
-            }
           }
-        }).error(function(response) {
-          MailPoet.Modal.loading(false);
         });
       });