Which countries are supported by Gemini?
Gemini support a large number of countries for user signup (a list can be found here).
However the countries able to link Brave Rewards to Gemini are more limited.
Currently only users in the United States are supported for linking Brave Rewards to Gemini.
This list is current as of 2022-11-16, and you can find the official Brave support article on the subject here.
If you had previously linked Brave to Gemini as a user from a now-unsupported country your Rewards will continue to transfer to the exchange while the connection is active. However when Brave naturally disconnects you (some time within a few months for most users), your Rewards will only then be able to accrue within the browser.