Microsoft confirms Exchange email outage was caused by free/busy infrastructure

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Are you encountering an Exchange email outage? If so, you’re not the only one. 

As spotted from @MSFT365Status, Microsoft confirms this issue (EX649175) that was preventing some users from sending Exchange Online email messages and has successfully mitigated the impact. The issue was caused by a recent change to the free/busy infrastructure, which is used to track the availability of users.

The issue was first reported on July 18, 2023, and Microsoft began investigating immediately. A fix was implemented within hours, and the issue was resolved for all affected users by July 19, 2023.

If you were affected by this issue, you may have received an error message when you tried to send an email message. The error message may have said something like “Unable to send message. Please try again later.”

“We’ve mitigated impact for EX649175. Please refer to the admin centre for more details. As the change was only applied to a limited portion of Exchange infrastructure, we’ve now scoped down our communication to only the customers who were affected by this issue,” says the Redmond-based tech giant. 

Even though Microsoft has not yet disclosed which regions were affected, they have taken prompt action in addressing the issue.

The free/busy infrastructure is a critical part of Microsoft 365, as it allows users to see when their colleagues are available. This is important for scheduling meetings and appointments, as it helps to ensure that everyone is available at the same time.

Have you encountered an Exchange email outage? Let us know in the comments!