diff --git a/lib/Kolab/DAV/Node.php b/lib/Kolab/DAV/Node.php
--- a/lib/Kolab/DAV/Node.php
+++ b/lib/Kolab/DAV/Node.php
@@ -206,7 +206,7 @@
         if ($error == \file_storage::ERROR_UNAVAILABLE) {
             throw new \Sabre\DAV\Exception\ServiceUnavailable($msg);
         }
-        else if ($error == \kolab_storage::ERROR_FORBIDDEN) {
+        else if ($error == \file_storage::ERROR_FORBIDDEN) {
             throw new \Sabre\DAV\Exception\Forbidden($msg);
         }