diff --git a/module/VuFind/src/VuFind/Controller/ErrorController.php b/module/VuFind/src/VuFind/Controller/ErrorController.php
index 5ba9f87c3a21bcc6117013c60bbfe7d36886d6fb..57ceb4120fe22a71d095168590f1c0fe6e53e639 100644
--- a/module/VuFind/src/VuFind/Controller/ErrorController.php
+++ b/module/VuFind/src/VuFind/Controller/ErrorController.php
@@ -47,6 +47,7 @@ class ErrorController extends AbstractActionController
      */
     public function unavailableAction()
     {
-        // no special action necessary
+        $this->getResponse()->setStatusCode(503);
+        return new \Zend\View\Model\ViewModel();
     }
 }