Payment verification failed when creating a child account

Hey,

i am giving away my old iPhone 14 Pro Max to my daughter. I have already created the Family Sharing, and when I want to create a new child account, after providing the first name, last name and the date of birth, I receive a "payment verification failed when creating a child account" error.

I followed lots of tutorials, deleted my payment method, added my PayPal account, added another payment method, checked the Media & Purchases, and verified I don't have any pending transactions- everything.

What else can be done??