diff --git a/lib/AccountManager/App.pm b/lib/AccountManager/App.pm
index 5600bc5ea44aa0de97abb2d2e2b14bca79d1c01c..3e5c852c91b323aa70c6c7f95e7e8f92680352cc 100644
--- a/lib/AccountManager/App.pm
+++ b/lib/AccountManager/App.pm
@@ -474,7 +474,7 @@ sub req_complete_challenge {
         entityid  => $entityid,
         token     => $token->secret(),
         challenge_url => sprintf(
-            '%s&action=complete_challenge&federation=%s&entity=%s&email=%s',
+            '%s?action=complete_challenge&federation=%s&entityid=%s&email=%s',
             $self->{configuration}->{app}->{url},
             $federation,
             $entityid,