Hey,
I´m also comfronting with the same problem, we got two shops and the both of them are working on the same credit card. On the first shop we already bought a new domain to change it from .myshopify in just .com .. so on the second shop we tried to do the same but it´s showing me the same warning and I´m not able to buy it.. I already tried your steps to clear the browser or to verify my Information. I also tried to switch different Browser and still not working.. what should I do to be able to buy a new domain for the second store?
Sorry for writing here but I really do need help and I would be greatful if you´d help me