No, that wasn't the problem. The problem was that Intuit auto-filled some of the order form fields with information, one of them being the phone number. I live abroad and so for some reason it didn't like the non-US number. After tens of attempts by deleting fields, using caps, etc., I randomly arrived at the solution - I deleted the prefilled phone number and it worked. Seems like a simple issue but I don't think anyone actually had a look at my specific problem.
