Microsoft Probes Exchange Online Outage EX1464935

Microsoft is actively investigating a new disruption in its Exchange Online service following numerous user reports highlighting access and mail-flow issues. This incident, identified as EX1464935 in the Microsoft 365 admin center, was first reported on August 31, 2026, at 9:23 PM IST. Within minutes, Microsoft confirmed that its engineers were examining the reported issues.

Current Status and Impact

At present, the disruption is still under investigation as Microsoft has yet to determine the root cause or the full scope of the problem. The advisory indicates that Exchange Online is the only service affected for now. However, similar incidents in the past have sometimes expanded to include other Microsoft 365 services like Outlook and Teams before being resolved. Administrators are encouraged to check the Service Health Dashboard for detailed, tenant-specific updates.

Historical Context of Exchange Outages

This latest issue is not an isolated event for Exchange Online. Earlier this year, Microsoft faced a comparable incident, EX1454755, which was traced back to a DNS issue with a third-party email provider. Additionally, a separate problem in June caused significant email delivery delays across various regions, including North America, Europe, and Asia-Pacific, with some messages delayed by over an hour.

Recommendations for Affected Users

Organizations relying on Exchange Online for business communications are advised to monitor updates in the admin center closely. Microsoft has indicated that recent disruptions have often been regionally contained or linked to external dependencies. IT teams should actively check mail queues, delivery reports, and connectivity if users experience delays or missing emails.

In a recent update, Microsoft confirmed that users might experience reduced functionality across various Exchange Online features. The company is reviewing service telemetry and diagnostics to isolate the issue’s source.

As Microsoft continues to analyze the situation, it remains committed to providing further updates. Users and administrators are encouraged to follow the latest developments through official channels to mitigate any potential disruptions.