Outage in Microsoft 365
Some users in the United States may be intermittently unable to access some Microsoft 365 services
Resolved Minor
March 18, 2026 - Started about 6 hours ago
- Lasted about 1 hour
Incident Report
Summary AI Generated
Microsoft 365 services, specifically Exchange Online and Microsoft Teams, experienced intermittent access issues for users in the United States due to a load balancing problem in the networking infrastructure. The issue occurred when only a subset of recently decommissioned networking infrastructure was reinstated to active service, causing improper traffic routing. Microsoft resolved the incident by manually reinstating the complete networking infrastructure and confirmed positive service health trends through monitoring.
Title: Investigating user reports of issues with Microsoft 365 products
User impact: We don't have details on impact yet. We're seeing an increase in user reported issues above our alerting threshold.
Current status: We are reviewing service telemetry and available information to determine if there is an issue happening and we'll update this message shortly with our latest findings.
This communication serves as a preliminary notification about a potential issue affecting your service.
Components affected
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Latest Updates ( sorted recent to last )
about 5 hours ago - at 03/18/2026 04:10PM
Title: Some users in the United States may be intermittently unable to access some Microsoft 365 services
User impact: Users in the United States may be intermittently unable to access some Microsoft 365 services.
More info: The following services may be impacted:
- Exchange Online
- Microsoft Teams
Current status: Our investigation has confirmed that a portion of our networking infrastructure that was recently removed from active service had only reinstated a subset of that removed infrastructure to active service, which led to a load balancing issue when rerouting service traffic. We've manually reinstated the entirety of the networking infrastructure slated for service load, and we're seeing positive trends on the service health. We're monitoring the service telemetry to ensure service recovers back to expected levels.
Scope of impact: Some users in the United States may be intermittently unable to access some Microsoft 365 services.
Next update by: Wednesday, March 18, 2026, at 5:00 PM UTC
about 6 hours ago - at 03/18/2026 03:32PM
Title: Investigating user reports of issues with Microsoft 365 products
User impact: We don't have details on impact yet. We're seeing an increase in user reported issues above our alerting threshold.
Current status: We are reviewing service telemetry and available information to determine if there is an issue happening and we'll update this message shortly with our latest findings.
This communication serves as a preliminary notification about a potential issue affecting your service.
Latest Microsoft 365 outages
Some users may have been unable to access Office.com or the Microsoft 365 Copilot web sign‑in page - 1 day ago
Some users may be unable to access Office.com or the Microsoft 365 Copilot web sign‑in page - 2 days ago
Some users may experience issues when accessing their Exchange Online mailbox via one or more connection method - 2 days ago
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