Email: Unexpected failure messages affecting some users

Incident Report for Cardiff University

Resolved

Microsoft has applied their updated fix to almost all of the infrastructure, and consider normal service to be restored for almost all users.

They do report that a small quantity of equipment is taking longer to receive the fix, so if you are still impacted by this issue please seek assistance by contacting University IT.
Posted Mar 18, 2025 - 09:35 GMT

Update

Microsoft have successfully completed testing the latest iteration of their fix, and are now deploying it.
They will provide the next update at 8pm Monday 17 March 2025
Posted Mar 17, 2025 - 16:15 GMT

Update

Microsoft continue to develop and improve their fix as they uncover additional complications to the issue.
They will provide their next update at 4pm Monday 17 March 2025
Posted Mar 17, 2025 - 11:02 GMT

Update

Microsoft completed rolling out their fix, but subsequently discovered that there was an additional aspect to the issue which resulted in the same symptoms, and are now developing an additional fix for this also.

Microsoft will provide a further update at 6:30pm Friday 14 March 2025
Posted Mar 14, 2025 - 09:24 GMT

Monitoring

Microsoft have partially deployed their fix, and expect full service to be restored for all users by the time of their next update at noon on Thursday 13 March 2025
Posted Mar 13, 2025 - 09:53 GMT

Update

Microsoft have updated that they have encountered an issue in deploying their fix, which is delaying the resolution.
They will provide a further update at 5pm Wednesday 12 March 2025
Posted Mar 12, 2025 - 09:34 GMT

Identified

Microsoft have informed us that a small number of users have been impacted by a bug which can prevent them from being able to successfully send or receive emails.

If you are affected by this issue, you may find that when you send an email you receive an automatic reply saying your message could not be delivered, and it will mention an error "554 5.6.0 Corrupt message content". Similarly, other people sending you emails may also find that it is not delivered to you.

Microsoft are preparing to deploy a fix for this issue, and will have more information at their next update at 6pm on Tuesday 11 March 2025 on how long it will take to fully restore service to those affected.
If you are affected by this issue, consider temporarily using alternative communication methods such as Microsoft Teams messages, until Microsoft can restore full service.
Posted Mar 11, 2025 - 10:16 GMT
This incident affected: Communication & Collaboration (Email & Calendar (Outlook)).