Problem med Mail via Exchange Online
Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.
Uppdatering 13.00
We’re seeing encouraging recovery progress in Europe, with service availability and email delivery performance improving across a growing portion of affected Microsoft 365 infrastructure. Japan remains comparatively more stable, while North America is also improving; however, some users may still experience intermittent issues as recovery actions continue.
We're focused on addressing the remaining areas of disruption and improving service consistency across affected regions. Reducing email queues and backlogs remains a priority, and the extended 48-hour email timeout window remains in place to help protect delayed messages as delivery catches up.
At this time, we have no evidence of malicious activity associated with this incident. We will continue to treat this with urgency until full mitigation, and we will share a full Post-Incident Report with root cause and defense-in-depth actions after mitigation is complete.
Uppdatering:
We’re seeing positive results for server stability after applying an upstream authentication/routing configuration component patch to a portion of our infrastructure. We’ll continue to monitor its progress and are working to expand it to servers supporting active regions coming online.
As of now, we are not aware of any malicious activity that is causing this incident. We will continue to treat this incident with urgency and priority until full resolution. Once mitigated, we will provide full details of the root cause, defense-in-depth repair items, and more within a Post-Incident Report.
Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API
Additionally, on-prem mail flow may be affected if it goes to or from Exchange Online.
Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.
13 nov. 2026 07:16 CET
As part of our ongoing efforts to advance the recoverability of our frontend servers, we’re evaluating traffic controls that can be applied to increase capacity and stability. This includes traffic optimization actions such as traffic throttling, protocol adjustments, and failover routing intended to improve stability in active regions. In parallel, were expanding internal testing to track activity within a contained environment to improve traffic monitoring and issue detection capabilities.
As of now, we are not aware of any malicious activity that is causing this incident. We will continue to treat this incident with urgency and priority until full resolution. Once mitigated, we will provide full details of the root cause, defense-in-depth repair items, and more within a Post-Incident Report.