I had the same problem and cant log in using the link in the previous post. - Kept getting invalid.
SO I launched the Discord desktop app and it asked me to sign in - email/phone # and password.
Once I did that, I went and clicked on the Discord link above and it worked. SO if you are a s dumb as me, this may be your answer. (Yes, I know its 4 years old, but at least the solution is recorded somewhere now)