Re: User 551, call billing and request refund on two days service
The error message 551 Not Our User is a response that came from the AT&T Yahoo! remote email server. It only affected Bellsouth members that have migrated to Yahoo! and are using client email software to send out emails.
This known outage (Event #161801) has already been resolved as of February 22, 2010 12:38:00 PM CST. Make sure you're using the following email server settings: