Thank you so much. That solved the proplem (almost). It still happens if I add a user to the Master Realm. After creating a new Realm, I can add Service Users as it should be. Thats fine for me - Thanks again 
Thank you so much. That solved the proplem (almost). It still happens if I add a user to the Master Realm. After creating a new Realm, I can add Service Users as it should be. Thats fine for me - Thanks again