Got an error in Linux Mint 19.3

THIS IS THE ERROR: HOW TO RESOLVE THIS ---------

Failed to fetch https://brave-browser-apt-release.s3.brave.com/dists/tricia/InRelease 403 Forbidden [IP: 151.101.158.217 443]The repository ‘https://brave-browser-apt-release.s3.brave.com tricia InRelease’ is not signed.Updating from such a repository can’t be done securely, and is therefore disabled by default.See apt-secure(8) manpage for repository creation and user configuration details.GPG error: http://dl.google.com/linux/earth/deb stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 78BD65473CB3BD13The repository ‘http://dl.google.com/linux/earth/deb stable Release’ is not signed.