Microsoft 365 outage takes down Teams, Exchange Online, Outlook


Level 76
Thread author
Honorary Member
Top Poster
Content Creator
Apr 24, 2016
Microsoft is investigating an ongoing outage impacting multiple Microsoft 365 services after customers have reported experiencing connection issues.

"We're investigating issues impacting multiple Microsoft 365 services. We've identified a potential networking issue and are reviewing telemetry to determine the next troubleshooting steps," the Microsoft 365 team said in a Twitter thread.

"We’ve isolated the problem to networking configuration issues, and we're analyzing the best mitigation strategy to address these without causing additional impact.

According to Redmond, users across all regions currently being serviced by the impacted infrastructure may be unable to access the affected Microsoft 365 services.

The list of services impacted by this outage includes Microsoft Teams, Exchange Online, Outlook, SharePoint Online, OneDrive for Business, PowerBi, Microsoft 365 Admin Center, Microsoft Graph, Microsoft Intune, Microsoft Defender for Cloud Apps, and Microsoft Defender for Identity, as revealed in a service health notification.
Update January 25, 04:39 EST: The Azure team says the root cause behind this outage was a recent Microsoft Wide Area Network (WAN) update. The update has now been rolled back.

"We have identified a recent WAN update as the likely underlying cause, and have taken steps to roll back this update," Microsoft says.

"Our latest telemetry shows signs of recovery across multiple regions and services, and we are continuing to actively monitor the situation."


Level 12
Aug 2, 2015
Windows Defender down too,?
icon shows a yellow warning and then the icon disappears completely from the system tray after a reboot
build 25281
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Level 19
Top Poster
Jan 21, 2018
The scenario faced today by people whose work environment involves many of the services that it uses being supplied by one organisation (Microsoft in this case) underlines to me a case for not putting all of your eggs in one basket. I get the argument put forward by those favouring many services from the one supplier, as they probably will be more compatible than services from numerous different suppliers. But, having witnessed the chaos today among workers when they could not access Teams, Outlook, OneDrive etc it was as if the foundations of the building they were all in had been ripped out and the upper levels teetered progressively more violently. Backup service systems exist, but lack of training leads to much unfamiliarity and no much getting done. Using one video conferencing system and a different suppliers email and messaging service along with anothers cloud services would most likely have resulted in the productivity being far less hampered than all of those services being down at the same time because they were all affected by this update failing.


Level 26
Top Poster
Aug 17, 2017
My Outlook is down 😩
About a couple of hours ago, system admins and IT admins started reporting online (via Reddit) about issues loading Microsoft 365 Admin Center, and problems in general across Exchange Online and Outlook on the web, among other places. However, some users claim that apps too are also affected and it is not just Outlook on the web. Soon enough, the official Microsoft 365 Status Twitter handle took to the social media platform to confirm those issues:

A while later, Microsoft updated the status adding that it was looking into the recent updates as it suspected that a recent change made could have broken something. The company informed that admins can monitor the situation using the Admin Center issue ID EX571516:

As suspected, Microsoft identified an issue with a recent update. The company added that it was reverting the update to mitigate the impact of the change (via nobody554 on Reddit):
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