Purchase could not be completed

I tried to purchase Robux in the Roblox app for my son’s device. After the 2 step verification process, it looks like it made the purchase, however, I immediately receive the error message stating that the purchase could not be completed and to please contact Apple support. I have 3 child accounts on my family sharing and my other 2 children are able to purchase things just fine. My Apple Card is linked and shared to all accounts on my family sharing, but for some reason, he’s the only one having the issues. This also happens on multiple apps, not just this one. Please advise on what I can do. Thank you.