SgtSurehand Yes, I think I did allow this when I first set up this user.
I just set up a test user now, and didn't aactivate 'turn on phone calls & sms'. And it works fine. Unfortunately, if I adapt the settings in the previous user account, it does not work. I will now compare the permissions and other settings between the the profiles, to find out, if there are any differences that could explain thedifferent behavior.