diff --git a/library/Icinga/Web/Form.php b/library/Icinga/Web/Form.php
index 054f7a89c..2beb09a5a 100644
--- a/library/Icinga/Web/Form.php
+++ b/library/Icinga/Web/Form.php
@@ -1169,9 +1169,7 @@ class Form extends Zend_Form
                         $this->getView()->layout()->redirectUrl = $this->getRedirectUrl()->getAbsoluteUrl();
                     }
                 } elseif ($this->getIsApiTarget()) {
-                    $this->getResponse()->json()->setFailData(
-                        array_merge($this->getMessages(), $this->getErrorMessages())
-                    )->sendResponse();
+                    $this->getResponse()->json()->setFailData($this->getMessages())->sendResponse();
                 }
             } elseif ($this->getValidatePartial()) {
                 // The form can't be processed but we may want to show validation errors though