Some users in the United States may be intermittently unable to access some Microsoft 365 services

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 have been intermittently unable to access some Microsoft 365 services. More info: The following services may have been impacted: - Exchange Online - Microsoft Teams Final status: We've confirmed that the service remains healthy after manually reinstating the entire network infrastructure that was slated for active service load and impact is remediated. Scope of impact: Some users in the United States may have been intermittently unable to access some Microsoft 365 services. Start time: Wednesday, March 18, 2026, at 2:00 PM UTC End time: Wednesday, March 18, 2026, at 3:08 PM UTC Root cause: A portion of networking infrastructure, slated for reinstatement to active service, had been only partially reinstated, which led to load balancing issues when handling service traffic. Next steps: - We're continuing our investigation into the partial reinstatement to better understand why this has occurred so we can determine how we can best avoid similar issues in the future. This is the final update for the event.

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

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.