I’ve had the same issue with my Brave Rewards for the last month or more. Every time I check, I get the, " Uh oh! The Brave Rewards server is not responding. We will fix this as soon as possible." It shows the rewards summary from the month, but the overall balance is never shown, meaning I can’t see my total rewards or use them on Uphold. For the record, I’m running Linux Mint and Brave Version 1.2.41 Chromium: 79.0.3945.88 (Official Build) (64-bit).