Family member can't activate Apple Music without own payment info

Hi.

My daughter's account is in my family sharing group and things work mostly fine. I have an active Apple Music subscription that is shared with the family. When she tries to start using Apple Music she is first asked for her login, then for her payment information, can't go on without that. She doesn't have any payment info of her own.

I ran into a vaguely similar problem earlier when I updated my payment info. Having moved from Germany to Sweden I had to first cancel subscriptions, then change country of residence, then payment info. My guess is that the payment the daughter's payment thing may be to do with that. Now her account is still localised to Germany and on the Apple ID webpage I am told that this cannot be changed at this time. (I am however not told WHY this cannot be changed).

Any suggestions?