Hey guys, I just got an American Express Gift card and am having trouble using here on GOG. I even called American Express and registered my card with them but GOG is still telling me that there's a problem with what I entered when I try to checkout on a purchase. Any ideas?

Could you post a link to the package you have? Odds are there's something in the T&Cs, but if you post a link then we can see.

Nevermind, it suddenly started working. Guess I just had to wait a bit after registration. Thanks, though!