As organizer of a family are you using the AppleID that purchases were initially made from?
When I try to turn on purchasing permission for my child, I get an error saying that the iTunes account is shared.
User profile for user:
Jason L
User level:
Community Specialist
Hello Drew-Bob,
It sounds like you’re setting up Family Sharing on multiple devices and using the same Apple ID. As the Organizer you should continue to use your Apple ID, then create a new Apple ID for your child as shown in the article below.
Family Sharing and Apple IDs for kids
I hope this helps,
-Jason