I cannot change the birth date. I keep receiving a "server error" if I (as a parent) want to approve the change.

I cannot change the birth date of my daughter (she is now an adult, but that's incorrect). I keep receiving a "server error" if I (as a parent) want to approve the change.

I logged into appleid.apple.com with her account. After I change the birth date, an parent confirmation is required. If I want to approve it, it fails.