This is because Brazil is not supported at this time. While Uphold may still support your country, Brave, Gemini, and Uphold made a joint decisions not to allow Brave to be connected for most countries until some issues are resolved. If you aren’t in one of the 19 approved countries on the list, you’ll need to wait until they open the regions again.
NOTICE: New region restrictions on verifying Brave Rewards with Gemini
NOTICE: New region restrictions on verifying Brave Rewards with Uphold