However, a specific user registered through facebook; but the email linked through his facebook is no longer active. He can't access it anymore.
So now he wants to change his email on his account. In order to change the email, you have to include a password. So now he needs to setup his password. But XenForo is sending his password setup confirmation to a dead email account... so he can't change his password.
Cant change his password, cant change his email.