You may need to try a different browser, but here's another link you can try; Discord.
Both links are not working for me. I tried with the Windows Desktop app, Edge, and Firefox. I get the error, "Unable to accept invite". Tried both clicking on the link and being redirected to the app, and directly putting in the invite link in the "Join a server" option in Discord.
Not sure if anyone else is seeing this error.
EDIT: Ah I see the issue. My account needed to be verified with a phone number.