ok
a couple of other things to check is that your running the most up to date brave browser but my guess is that’s not the issue.
By searching the community I see there was someone reporting a similar issue a while back https://community.brave.com/t/unable-to-link-brave-to-gemini/286481.
Might be worth DM one of the main support people I see @Mattches on the thread I mentioned, but there are others
Good luck and hope this helps