TL;DR: ChatGPT Plus and Claude Pro can reject a perfectly good card because your country is not on their billing list. The card is not the problem. The billing country is.
This one confused me for a while. My card was fine, address matched, no fraud flag, and OpenAI still bounced the Plus upgrade. Claude Pro did the same. Different failure from a normal decline, and the fix is different too.
Disclosure: I work on Fizen, one of the crypto-card options I mention below. The non-Fizen options are here because they genuinely work.
A normal Stripe decline is a risk score. This is a policy gate. OpenAI and Anthropic only sell subscriptions in a list of supported countries, and they infer your country from a few signals:
If those say "unsupported country," you get a clean rejection with no useful error. It is not fraud. It is geography. A VPN alone almost never fixes it, because the card BIN still says where you are. The signal that counts most is the card's issuing country, so that is what you change.
Whichever you pick, set the billing country on the form to match the card, not your home address. Mismatched country is the most common reason these still fail.
Same trap exists on a bunch of AI tools right now. If you hit it on a specific one, name the tool and your country in the comments.
Longer breakdown, with the supported-region notes and which cards map where, is here.