I can’t make purchases in apps

Hello, I can’t make in-app purchases and I keep getting an iTunes or billing related error. It has been happening for several days now. I can download free apps and subscribe to other apps or games, but I can’t make purchases inside games or activate Roblox Plus in Roblox. I already signed out and back into my Apple ID, restarted my iPhone, and verified my payment method. Could you please check my account and help unblock purchases?