What's your issue with the authentication process ? Any error showing? Is it stuck in a loading state?
Do you reach the authentication page on itchio (or patreon?)?
Are you able to authenticate on the page?
Does it send you back on our download portal?
The manual token requires you to go through the authentication process on our portal but instead of sending the token to the game, you have to copy/paste from the portal.
If you're having trouble to authenticate with you itchio/patreon account it won't help.