Child's apple cash set-up repeatedly unsuccessful "apple cash unavailable" message

Hello,

I have 2 child accounts under our shared family plan for my 11 &12 year olds. I have attempted multiple times over the course of several months and many attempted fixes to set up apples cash for my 12 year old, now consistently receiving "apple cash not available at this time" error. We have confirmed all phone settings as advised in online searches. On a whim I attempted to set up for my 11 year old, just to check, and that went through without issue. I believe I have all the same settings/restrictions set to both accounts so I cannot figure our why we are having this consistent problem. Any advice?

Thank you!