Microsoft Tests Fix for Hours-Long Outlook Outage – Innovation Village

Microsoft is testing a fix for a widespread Outlook outage that disrupted email and other Exchange Online services for users on Monday.

The company confirmed that the incident was affecting its Exchange Online platform, the cloud service that powers business email, calendars, contacts and tasks across Microsoft 365.

The outage caused problems including delayed or failed emails, authentication errors, mailbox search failures and other disruptions to everyday workflows.

Microsoft identifies authentication issue

Microsoft initially said it was investigating reports of problems with Exchange Online before confirming that the incident was linked to an authentication component.

In an update posted on X at 12:43 p.m. ET, the company said users were experiencing degraded functionality across various Exchange Online features and that its engineers were reviewing service telemetry and diagnostic data to identify the source.

Microsoft later said it had isolated an issue involving an authentication component and developed a remediation strategy.

The company began applying the proposed fix to a portion of its infrastructure to test whether it would resolve the disruption.

If the test proves successful, Microsoft said it will expand the remediation across its wider infrastructure.

The problem extends beyond Outlook

The authentication issue is not limited to Exchange Online.

In a subsequent update, Microsoft said its investigation had confirmed that the affected authentication component was also impacting other Microsoft services.

The company said its engineers were continuing to fine-tune the remediation strategy while internal testing was underway.

This means some users could experience problems beyond email and mailbox functions, depending on which Microsoft services rely on…