Somehow one of my members made a bad account with a bad email address. email@example.com. Obviously the "2" shouldn't be there. He made the account while trying to regain access to his old (good) account. I have since gone in and gotten him reconnected with his old account, and have deleted the @2gmail.com account, but the system keeps trying to send registration emails to the bad account, bouncing, and sending me an email message reporting the error. After 3 days it is getting annoying. How do I stop/purge the email queue - particularly when it is sending out an email referring to a deleted account?
Odds are the problem is with your MTA and not XenForo. You processed that email to send, and it was then handed off to whatever MTA you use to send emails... which is now continuing to try and send it. You will need to remove it from the MTA's queue.