diff --git a/Services/WebServices/ECS/classes/Course/class.ilECSCmsCourseMemberCommandQueueHandler.php b/Services/WebServices/ECS/classes/Course/class.ilECSCmsCourseMemberCommandQueueHandler.php
index 284bd2e8fb57..09adf4815392 100644
--- a/Services/WebServices/ECS/classes/Course/class.ilECSCmsCourseMemberCommandQueueHandler.php
+++ b/Services/WebServices/ECS/classes/Course/class.ilECSCmsCourseMemberCommandQueueHandler.php
@@ -431,7 +431,7 @@ private function createMember($a_person_id): void
             $query = new ilLDAPQuery($server);
             $query->bind(ilLDAPQuery::LDAP_BIND_DEFAULT);
 
-            $users = $query->fetchUser($a_person_id);
+            $users = $query->fetchUser((string) $a_person_id);
             if ($users) {
                 ilUserCreationContext::getInstance()->addContext(ilUserCreationContext::CONTEXT_LDAP);