Microsoft is investigating a service disruption affecting multiple products, including Outlook, Microsoft Teams, Azure, and Microsoft Defender. Reports of connectivity issues began around 2:30 PM ET on January 22, 2026. This incident is tracked under the ID MO1221364.

MO1221364: Users may be unable to access various Microsoft 365 services. We are investigating a potential issue and will provide an update when more information is available.

Current Status: Tracking

Note: This post is a tracking entry. It will be updated as technical details and fixes become available from Microsoft.

What is happening with MO1221364?

The disruption is widespread, impacting both web applications and desktop clients. While initial reports centered on Outlook, the scope now includes Microsoft Purview, Microsoft Defender, and Azure services. Users are seeing authentication failures, slow response times, or complete service outages.

If you are experiencing local application crashes rather than network errors, check if your issue matches a known fix Outlook error 0xc0000409 entry, though MO1221364 appears to be infrastructure-related.

Why this service disruption occurs

While Microsoft has not yet released a formal root cause analysis, disruptions of this scale typically stem from one of three areas:

  1. Configuration Changes: A change to network routing or DNS settings can prevent traffic from reaching Microsoft data centers.
  2. Authentication Service Failures: If the Entra ID service slows down, users cannot log into any connected services, even if individual apps like Teams are technically online.
  3. Infrastructure Failover Issues: Unexpected traffic spikes or hardware failures in primary data centers can sometimes fail to transition to redundant systems.

For IT administrators, checking your tenant status via the Microsoft 365 Admin Center helps. If you cannot access the portal, monitor official service health channels for real-time updates.

Since this is a server-side issue, local troubleshooting usually won't work. However, administrators can do the following:

  • Check Service Health: Log in to the Admin Center and navigate to Health, then Service health.
  • Communicate with Users: Notify your organization that this is a global Microsoft issue to reduce help desk tickets.
  • Review Logs: Use PowerShell scripts to check for connection errors if you suspect the issue is restricted to your network.

If you need help navigating your tenant health or investigating local network conflicts during this outage, contact us.

Timeline of Events

  • 2:30 PM ET: Initial spike in reports across monitoring sites.
  • 3:00 PM ET: Microsoft acknowledges the issue and assigns incident ID MO1221364.
  • Ongoing: Microsoft engineers are investigating the infrastructure to find the source of the disruption.

We will update this post as soon as a workaround or a permanent fix is announced.

Need hands-on help? Contact our team.

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