diff --git a/application/forms/MoveNodeForm.php b/application/forms/MoveNodeForm.php
index 06ada01..d261eac 100644
--- a/application/forms/MoveNodeForm.php
+++ b/application/forms/MoveNodeForm.php
@@ -154,7 +154,9 @@ class MoveNodeForm extends QuickForm
                 $this->parentNode !== null ? $this->parentNode->getName() : null
             );
         } catch (ModificationError $e) {
-            $this->notifyError($e->getMessage())
+            $this->notifyError($e->getMessage());
+            Icinga::app()->getResponse()
+                ->setHttpResponseCode(400)
                 ->redirectAndExit($this->getSuccessUrl());
         }