Microsoft 365 outage hit Teams, Exchange Online, and Outlook before Microsoft restored service

Microsoft 365 suffered a short but broad service disruption on April 8 that affected access to core services including Microsoft Teams, Exchange Online, Outlook, and parts of the wider Microsoft 365 suite. Microsoft has since restored service and said the issue stemmed from changes made by an external network provider that disrupted traffic routing.

The incident was tracked under MO1274150. Microsoft’s public-facing incident history, mirrored by the University of Pennsylvania’s Microsoft 365 incident page, shows the outage started at 2:38 PM UTC and ended at 3:05 PM UTC, with users seeing intermittent delays in email delivery and trouble accessing Microsoft 365 services.

Microsoft’s latest status says service has recovered fully. The company added that users in North America and Europe were affected most, with many of the customer reports coming from the United States, the Netherlands, the United Kingdom, and Canada.

What happened

Early updates from Microsoft said it was investigating issues across multiple Microsoft 365 services, including Teams and Exchange Online. A later update said an external service dependency contributed to the impact and that recovery signs had already started to appear.

Microsoft then said its recovery mechanisms had kicked in and that internal telemetry, along with customer reports, pointed to rapid improvement. Shortly after that, the company said it had identified and corrected the network-level disruption, while warning that some Exchange Online users could still face brief email delivery delays during the final remediation stage.

The final explanation is more specific than the early updates. Microsoft said configuration changes by an external network provider affected internet traffic routing, which then caused connectivity issues across multiple Microsoft 365 services. To restore availability, Microsoft redirected traffic through alternate network paths.

Incident timeline

Time	Update
2:38 PM UTC	Incident started
2:43 PM UTC	Microsoft began investigating issues affecting multiple Microsoft 365 services
3:31 PM UTC	Microsoft said an external service dependency was contributing to the disruption
3:32 PM UTC	Microsoft said automated recovery actions were improving service health
3:37 PM UTC	Microsoft said it had corrected the network-level disruption, though some email delays could remain
3:05 PM UTC	Official end time listed in incident history
12:02 PM ET update log	Microsoft confirmed full recovery and healthy telemetry

Source basis for the timeline and recovery sequence: Microsoft incident details mirrored on PennO365’s Microsoft incident page.

Who was affected

Microsoft said the disruption mainly hit users in North America and Europe. The company did not publish a total user count, but the incident covered some of its most widely used business services, which means the impact likely reached organizations across several regions at once.

User impact centered on intermittent access problems and email delays. Microsoft’s incident notes specifically mention trouble using Microsoft 365 services and delayed email delivery, which fits reports from admins who could not reliably reach Teams, Outlook, and related services during the event.

Microsoft also says admins can use the Microsoft 365 admin center’s Service health page to track active incidents and recent issue history. If admins cannot sign in, Microsoft points them to the public service status page and its Microsoft 365 Status account on X for certain incident updates.

What Microsoft said

Here are the most important official statements tied to this outage:

• “We’ve identified an external service dependency” contributing to impact across multiple Microsoft 365 services.
• “Service health is improving rapidly” after Microsoft’s recovery mechanisms took action.
• “Service health has been restored” across affected Microsoft 365 services.
• Preliminary root cause: changes by “an external network provider” affected traffic routing.

What the root cause means

This was not described as an Exchange bug, a Teams app failure, or a Microsoft 365 tenant-specific misconfiguration. Microsoft’s incident history points instead to network routing problems caused by an external provider change, which then affected access to several Microsoft 365 services at the same time.

That distinction matters for admins. When a routing issue hits shared service access paths, multiple products can appear broken at once even when the apps themselves remain healthy. Microsoft’s mitigation step, redirecting traffic through alternate paths, also supports that reading of the event.

We're investigating an issue that's affecting multiple Microsoft 365 services. We're reviewing available data and will provide additional updates to MO1274150 in the admin center.

— Microsoft 365 Status (@MSFT365Status) April 8, 2026

Microsoft says it will keep analyzing the systems involved and work with the external provider on safeguards to help prevent a repeat. The company also said it will not publish a post-incident report for this event because it determined the trigger came from an external network provider.

Quick takeaways for admins

Area	What to know
Incident ID	MO1274150
Main affected services	Microsoft Teams, Exchange Online, Outlook, broader Microsoft 365 access
Main impact	Intermittent access issues and delayed email delivery
Main affected regions	North America and Europe
Root cause	External network provider configuration changes affected routing
Mitigation	Microsoft redirected traffic through alternate network paths
Current status	Restored

What admins should do next

• Review the incident history for MO1274150 in the Microsoft 365 admin center.
• Check whether users still see delayed mail delivery or cached sign-in issues.
• Compare local networking alerts with the outage window before opening internal escalations.
• Set up Service health notifications in the Microsoft 365 admin center.
• Follow Microsoft 365 Status for public updates when admin center access is limited.

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