diff --git a/modules/ldap/lib/Auth/Process/AttributeAddUsersGroups.php b/modules/ldap/lib/Auth/Process/AttributeAddUsersGroups.php
index 6101e7b162921c732d4db64baab3ca827f0c9eb1..fc66ec57f5f8bc6307b550563ead6ec4d72edf70 100644
--- a/modules/ldap/lib/Auth/Process/AttributeAddUsersGroups.php
+++ b/modules/ldap/lib/Auth/Process/AttributeAddUsersGroups.php
@@ -171,7 +171,7 @@ class AttributeAddUsersGroups extends BaseFilter
 
         // run through all groups and add each to our groups array
         foreach ($all_groups as $group_entry) {
-            $groups[] .= $group_entry[$map['member']][0];
+            $groups[] = $group_entry[$map['member']][0];
         }
 
         return $groups;