Can’t give permission to my child’s account

Can't give permission to my child's account                I see this on the forum and it seems the answer is to clear browser settings and try a different browser.  does not work.  I've tried 4 different PC's, Different networks, etc...  When I try to give my son permission to use the account, I get a technical error.  This occurs after I get through all the screens, including adding a credit card number, then it says there is a technical error.   "We're unable to complete your re