diff --git a/plugins/kolab_auth/kolab_auth.php b/plugins/kolab_auth/kolab_auth.php
index fc0158ba..719df98c 100644
--- a/plugins/kolab_auth/kolab_auth.php
+++ b/plugins/kolab_auth/kolab_auth.php
@@ -337,7 +337,7 @@ class kolab_auth extends rcube_plugin
             // check group
             if (!$isadmin && !empty($group)) {
                 $groups = $ldap->get_record_groups($record['ID']);
-                foreach ($groups as $g) {
+                foreach ($groups as $g => $prop) {
                     if ($group == rcube_ldap::dn_decode($g)) {
                         $isadmin = true;
                         break;