Microsoft Exchanges Online for Troubled Users

Microsoft is investigating a widespread service issue affecting Exchange Online customers, causing authentication issues and email delays and failures. The incident, tracked under EX1464935 in the admin center, was first acknowledged at 5:30 PM UTC after users reported problems on social media.

According to Downdetector, tens of thousands of Exchange Online users are experiencing issues receiving emails via Outlook and accessing the Exchange Online platform. Microsoft has identified a common failure pattern across affected requests associated with authentication and protocol connectivity.

The company is analyzing service telemetry to identify the underlying source of impact and validate potential remediation options. This is not the first time Microsoft has addressed multiple Exchange Online outages in recent months, having mitigated similar issues in June and April.