We're testing a configuration change to address a problem that's causing servers to fail automated health checks and become unavailable. In parallel, we've initiated a restart of all affected servers and are monitoring health as they return to service.
Posted Nov 12, 2026 - 13:10 MST
Update
We are continuing to work on a fix for this issue.
Posted Nov 12, 2026 - 12:48 MST
Update
Microsoft update:
Nov 12, 2026, 12:18 PM MST We've determined that the elevated load isn't driven by an overall increase in traffic, but by a large number of servers being unexpectedly unavailable, which is shifting load onto the remaining infrastructure. We're investigating what's causing these servers to become unavailable while we work to safely return them to service. This quick update is designed to give the latest information on this issue.
Posted Nov 12, 2026 - 12:47 MST
Identified
The issue has been identified and a fix is being implemented.
Posted Nov 12, 2026 - 11:07 MST
Investigating
From Microsoft:
Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods
Issue ID: EX1550543 Affected services: Exchange Online Status: Service degradation Issue type: Incident Start time: Nov 12, 2026, 9:17 AM MST
User impact Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.
More info Potentially impacted connection methods may include: - Outlook on the web - Messaging API (MAPI) - Exchange ActiveSync (EAS) - Representational State Transfer (REST) API
Scope of impact This issue may affect users in North America, Latin America, Canada, and Chile.
Current status Nov 12, 2026, 10:45 AM MST We’ve identified connectivity errors occurring on a portion of Exchange Online infrastructure which receives and processes users’ access requests. We’ve collected networking logs to review to further investigate the source of these errors and confirm our next steps. Next update by: Thursday, November 12, 2026 at 1:00 PM MST
Posted Nov 12, 2026 - 11:07 MST
This incident affects: Email/O365 applications (Email).