Microsoft 365 Service Outage Impacts Exchange Online, Teams, OneDrive and Other Services
August 31, 2026
Microsoft is investigating a widespread Microsoft 365 service disruption affecting Exchange Online and several other cloud services. Users have reported email delays and failures, authentication problems, connection issues, and difficulty accessing Microsoft 365 applications.
Microsoft initially identified the Exchange Online incident as EX1464935 after receiving widespread reports of service problems. Microsoft is now tracking the broader Microsoft 365 incident as MO1465074.
What Microsoft 365 Services Are Affected?
While Exchange Online appears to be experiencing the most significant impact, Microsoft has confirmed that the incident is also affecting:
- Exchange Online and Outlook
- Microsoft Teams
- OneDrive for Business
- SharePoint Online
- Microsoft Purview
- Microsoft Defender XDR
According to Downdetector’s Outlook status page and Microsoft 365 status page, tens of thousands of users have reported problems accessing Microsoft cloud services or receiving email.
What Are Users Experiencing?
Microsoft has identified several symptoms related to Exchange Online, including delays or failures when sending and receiving email, authentication errors, problems accessing Exchange administration tools, incomplete or delayed mailbox searches, and intermittent failures involving mailbox operations and message delivery.
Microsoft’s Microsoft 365 Status account has also been providing information regarding the disruption.
What Is Causing the Microsoft 365 Outage?
As of Microsoft’s August 31 update, the company has traced the problem to core authentication configuration issues within the Exchange Online infrastructure.
Microsoft stated that it identified issues involving a core authentication configuration used by multiple internal Exchange Online services. Engineers are testing configuration resets at the individual server level to determine whether the changes resolve the problem.
The company continues to analyze service telemetry, evaluate the full scope of the outage, and work toward restoring normal service.
What Should Microsoft 365 Customers Do?
If your organization is experiencing email delays, authentication failures, Teams connectivity problems, or difficulty accessing OneDrive, SharePoint or other Microsoft 365 services, the issue may be related to this Microsoft service disruption rather than your organization’s local network or devices.
Microsoft 365 administrators can monitor incident MO1465074 through the Microsoft 365 Admin Center Service Health dashboard.
M3 Tech will continue monitoring the situation as Microsoft works to restore normal Microsoft 365 services.
If your organization is experiencing Microsoft 365 connectivity, email, or authentication issues and needs assistance determining whether the problem is related to this outage or your local environment, contact M3 Tech for support.
