diff --git a/modules/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ZimbraPreAuth.pm b/modules/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ZimbraPreAuth.pm
index 3e0079ec2..7f6fde4db 100644
--- a/modules/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ZimbraPreAuth.pm
+++ b/modules/lemonldap-ng-handler/lib/Lemonldap/NG/Handler/ZimbraPreAuth.pm
@@ -122,6 +122,7 @@ sub _buildZimbraPreAuthUrl {
     $zimbra_url .= $url;
     $zimbra_url .= '?account=' . $account;
     $zimbra_url .= '&by=' . $by;
+    $zimbra_url .= '&timestamp=' . $timestamp;
     $zimbra_url .= '&expires=' . $expires;
     $zimbra_url .= '&preauth=' . $computed_value;