I have done all the troubleshooting at Error message “Purchase failed.”, plus adding new cards, deleting and adding the same card, trying PayPal and nothing seems to work. I have opened two cases with Zendesk on this site and called to get phone support from Microsoft Store and XBOX. Each group keeps passing me around to the next. Does anyone else have any additional ideas?
I’ve had the same problem. The workaround that got me through was to launch MSFS 2020 from the Xbox Console Companion. If you do that, the Marketplace works; at least for me. Good luck.