diff --git a/lib/API/JSON/API.php b/lib/API/JSON/API.php
index 9ebab1a9c8..7421ffc3d4 100644
--- a/lib/API/JSON/API.php
+++ b/lib/API/JSON/API.php
@@ -57,7 +57,7 @@ class API {
     $this->setRequestData($_POST);
 
     if($this->checkToken() === false) {
-      $error_message = __('Invalid API request.', 'mailpoet');
+      $error_message = __('Sorry, but we couldn\'t connect to the MailPoet server. Please refresh the web page and try again.', 'mailpoet');
       $error_response = $this->createErrorResponse(Error::UNAUTHORIZED, $error_message, Response::STATUS_UNAUTHORIZED);
       return $error_response->send();
     }
@@ -200,4 +200,4 @@ class API {
     );
     return $error_response;
   }
-}
\ No newline at end of file
+}