Another one! Yep, happened to me when my ISP's mailserver went down. TRF tried to send me mails which bounced and I ended up with the same message.
Either that or you've been banned.
Once the ISP's server was back up, I changed the email address of my username to another email I have. Once that was accepted I changed it back to the original email. Long workaround, but TRF wouldn't let me just re-authorise the same email address.
Good luck!