Please see the following Help Center topic to check if you are in a supported region for Brave-Uphold connections.
If your country is not in the list, you can still view ads and earn Rewards if you are eligible (see Transparency Data Feed | Brave Browser and Regional Catalog Viewer ). Your Rewards wallet will be unverified and payouts will show up in your Rewards panel balance.
If you were receiving payouts to Uphold even though your country was not in the list, then the below quoted text from the Brave support staff notice probably applied.
NOTICE: New region restrictions on verifying Brave Rewards with Uphold
Note that those who are currently verified in regions that are no longer supported will continue to be until they are naturally logged out over time, or press to disconnect Brave Rewards from their Uphold account. Once logged out or disconnected from Uphold, users in unsupported regions will not be able to log in again or re-verify Brave Rewards with Uphold.
If your country is still supported for Brave-Uphold connections (able to be verified) then you should not be receiving this message. If this is your scenario, you submit a request for support to investigate using the form linked below.
Hope this helps. Please post an update. 