It just means info going from your computer to the server is no longer encrypted so others in the path can read it.
Might disclose your isp and other things to third parties.
"files.catbox.moe normally uses encryption to protect your information. When Brave tried to connect to files.catbox.moe this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be files.catbox.moe, or a Wi-Fi sign-in screen has interrupted the connection. Your information is still secure because Brave stopped the connection before any data was exchanged.
You cannot visit files.catbox.moe right now because the website uses HSTS. Network errors and attacks are usually temporary, so this page will probably work later."
BeatUpAll -10 points 1 year ago
If you weren’t antisocial chuds, you could just use Imgur instead of relying on shitty alternatives.