Invitation for family sharing to son it says he needs a valid credit card to join?

[iMore Question]

invitation for family sharing to son it says he needs a valid credit card to join

I want to share an app I have with my son. He has had to switch bank cards so the one he has on file isn't correct he is waiting on new credit card. I have a card on file and I send him an invitation for family sharing and when he tries to accept it he gets a message that he needs to have a valid card on file.

 

[kch50428]

Re: invitation for family sharing to son it says he needs a valid credit card to join

Buy a $10 iTunes card and have your son apply that to his AppleID...