ceerker I don't know if it is the case, but suppose you go to
https://indieclub.one, click the login inside Flarum, get redirected to
account.indieclub.one for login, and then get redirected to
https://www.indieclub.one, this could cause an error like the one you have.
If you have setup canonical urls correctly (I suppose you have) it should always redirect to www so this wouldn't be possible.