If you can't log in

Pick the one closest to your situation.

The email code doesn't arrive or doesn't work
Check your spam folder too. You can send one code per minute to the same address. Codes stop working after 10 minutes, so use the code from the newest email.
Log in with email
Discord login fails
This happens if you didn't allow it on Discord's screen, or if too much time passed. Try again from the login page.
Back to the login page
If you still can't log in
You can contact support without an account. Say which screen showed what.
Contact

The email code doesn't arrive or doesn't work