Having the same problem. To confirm, I am trying to upgrade to a paid account, but even when entering my business address and credit card information correctly, I get the error below:
Oops! We couldn't set up this subscription, please report this issue if it persists.
I also get the same error if I try to input just my business address in the settings page.
I finally got this to work for me. For me, it was that the IP address i was connected to the internet with was far away (a state over) from the zip code on the billing address for the CC. So I think having your IP close to the zip on the CC matters.