Can’t update Payment method problem. iOS 12.4. iPhoneXS Max

Because one can only access the in-app purchases setting through the iPhone settings (as far as I know). If I go to Settings/Apple ID/Sign in to iTunes Store/Payment & Shipping, I receive “We’ve run into a problem. Please try again later.” This happened a couple of months ago, but resolved after a week. This current situation has lasted 6 weeks.

Of course. That’s true. Sorry. However, I still cannot access payment details on my iPhone. Simply, that makes me nervous. Why do I receive that error message now? It worked in the past.

Thank you for your help & your patience.

Thank you once again. I’ll continue to slog through possibilities as they occur!

Yes, by going through route above I was able to update card number, but I still cannot access choices on phone, like turning in-app purchases off/on.