It could be simply technically related, or not as simple but financially logistically related. In the past, ttax has had touchy issues requiring the turbotax web address listed in the "Allowed" or "Safe" sites area of the browser. That usually was why I previously saw similar payment failures as you describe.
Another possibility could be the transaction processor. The bank might disallow Intuit's request for payment, out of abundance of caution; or the typical practice of, for example, 4-digit PIN numbers by many banks overseas might not be accepted anymore by U.S. payment processors.
