Usually you get the specific Error Message for that, but yours could be a mix of issues. Just so you know, it’s possible your region really isn’t supported. Brave has had a lot of issues this year and restricted the ability to link to Uphold or Gemini down to 19 countries. So if you’re not in one of those countries, you wouldn’t be able to link, even if you’ve used it before.
You can read in extensive detail in my Topic where I’ve been providing regular updates. That can be seen at PSA: Unsupported Region
Otherwise main official article is https://support.brave.com/hc/en-us/articles/6539887971469