i've heard of this before. this might sound silly, but try a different browser. for some reason, some browsers really don't like discord invites, and they somehow mess them up before actually redirecting you to them.
if that doesn't work, add me on discord (same username and avatar as here) and i'll directly invite you
sorry about the inconvenience!
Please ignore this as user error. I was apparently signed in (or half signed in, with an unverified account?) in my web browser, with a different account from the Discord application itself, and the error message Discord gave was generic enough that I didn't clock the source of the problem right away. It worked when I joined it from Discord itself, so no worries!
