Unified Technology Solutions experienced a critical incident on May 8, 2024 affecting Other 3rd Party Issues, lasting 13d 1h. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- identified May 08, 2024, 03:51 PM UTC
It appears there are issues sending to users with @att.net email addresses, AT&T has not released much info but we do know that it has been going on since yesterday and the outage ticket number is 1605187 and it affects all email providers trying to send to @att.net email addresses.. We will continue to monitor this the best we can but as it is an outside service and they are not publicly announcing it we can not provide much more info. What this means for you is you may start to see bounce messages today from emails you sent yesterday to @att.net email addresses with the error code: 450 4.4.316 Connection refused" or "'550 5.4.316 Message expired, connection refused". Mail servers will try a few times to send the message with this error so there will be a delay from the time it is sent until you receive this message.
- monitoring May 08, 2024, 03:57 PM UTC
We have now been made aware that sending @bellsouth.net email addresses are also affected by this issue. We have also ran manual checks on AOL and Yahoo as they are owned by AT&T and confirmed they are working.
- monitoring May 10, 2024, 02:59 PM UTC
Inhouse testing this morning shows some email sent to att.com/.net, bellsouth.com/.net, and @sbcglobal.net domains are still being delayed by AT&T, we will continue to monitor this situation and run test periodically until we see it is resolved. We have also been able to locate an official, but very limited on detail, statement from AT&T about the issue. https://www.bleepingcomputer.com/news/technology/att-delays-microsoft-365-email-delivery-due-to-spam-wave/
- resolved May 21, 2024, 05:44 PM UTC
It appears messages to AT&T and Bellsouth are being delivered so we are closing this incident.