Users may be unable to connect to multiple Microsoft 365 services.
- Status
- Eingeschränkt
- Funktion
- Access
- Region
- Nicht angegeben (alle Regionen)
- Beginn
- 12.11.2026, 19:26 Uhr
- Dauer
- 10 Std. 24 Min.
- Letztes Update
- 13.11.2026, 05:12 Uhr
- Nächstes Update
- 13.11.2026, 06:00 Uhr
Aktueller Stand
We’re continuing our efforts to improve server stability to improve traffic flow. This includes adjusting traffic protocols, redistributing traffic, and applying strategic traffic blocking measures.
We're observing partial recovery across regions in which we've applied these adjustments; however, these actions aren't resulting in sustained recovery, so we're reviewing what additional actions we can take to improve overall infrastructure stability.
Mehr Informationen
Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.
- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Failures may occur for scenarios including access to Safe Links, Safe Attachments, protection and submission policies, and attempts to view Quarantine, Threat Explorer, and Email remediation events. Additionally, delays may occur for Tenant Allow / Block list changes, unified Role-Based Access Control, reporting, message traces, content extraction, and outbound protection. Users clicking on wrapped/rewritten URLs typically processed by Safe Links will result in a failure to navigate, as Safe Links fails to process it. Users who are able to successfully access the Quarantine portal may encounter failures when attempting to release items from quarantine.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or openin
Betroffen
This issue may affect users attempting to access the affected Microsoft 365 services.
Verlauf
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- 13.11.2026, 05:12 Uhr
We’re continuing our efforts to improve server stability to improve traffic flow. This includes adjusting traffic protocols, redistributing traffic, and applying strategic traffic blocking measures.
We're observing partial recovery across regions in which we've applied these adjustments; however, these actions aren't resulting in sustained recovery, so we're reviewing what additional actions we can take to improve overall infrastructure stability. - 13.11.2026, 04:36 Uhr
As part of our investigation into the sustained traffic management imbalances, we’re reviewing traffic flows and affected infrastructure to identify opportunities to optimize routing. This includes verifying the reasons for service failures so we can develop specific actions to improve stability.
We will continue to share more information as soon as we have it, and for now we can confirm that there is no indication this is the result of malicious activity. We’ll continue to apply learnings towards remediation actions as we confirm effectiveness mitigation actions. - 13.11.2026, 03:58 Uhr
We’ve monitored the status of the changes applied to improve serviceability and confirmed that change is not taking as expected. We’re identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances.
- 13.11.2026, 03:10 Uhr
We’re applying infrastructure capacity improvements where possible in an effort to help support traffic in regions coming online. We’re continuing to monitor the results of changes applied so we can identify strategic actions that can help to improve service health across all affected regions.
- 13.11.2026, 02:48 Uhr
We’re seeing positive results with our efforts to restart affected infrastructure. We’re actively monitoring the performance of these to verify stability which will support improved availability. Remediation actions will be expanded as we confirm stability with the changes applied.
- 13.11.2026, 02:12 Uhr
Our investigation has found that a process on the affected servers responsible for establishing secure connections becomes overwhelmed, causing the servers to stop processing requests. We're preparing a configuration change to address this behavior that can be applied across all affected servers, and we're validating it on a subset of servers before applying it more broadly alongside restarts of the affected infrastructure. In parallel, we've begun reverting a recent network configuration change that correlates with the start of impact and are monitoring to determine whether this contributes to recovery.
The temporary traffic limitations we previously described are now in effect in specific locations. We're monitoring the affected servers in those locations to confirm whether they remain stable while handling a narrower set of connections, after which we'll gradually reintroduce additional traffic. - 13.11.2026, 01:45 Uhr
We've reviewed known impact scenarios and have revised the list of impact services and features, which can be viewed in the "more info" section of this communication.
We're continuing our work to isolate the issue affecting server availability, as well as other workstreams. - 13.11.2026, 01:00 Uhr
While the servers we've returned to service initially remain healthy, we've observed that they can become unresponsive again once they begin receiving traffic. We're analyzing diagnostic data from these servers with our networking and platform experts to determine what's triggering this behavior.
Building on the protective traffic management measures we've implemented, we're also temporarily limiting which types of traffic can reach the affected infrastructure in specific locations. This will help us determine whether a particular type of request is contributing to the impact and allow us to restore service incrementally. Additionally, we're rebuilding a subset of affected servers using a previous software configuration to validate whether this prevents them from becoming unresponsive, and we'll expand this approach to additional servers if we observe positive results. - 12.11.2026, 23:58 Uhr
We've begun returning a portion of the affected servers to service, and they're remaining stable so far. We’ve also shifted traffic and connections to alternative pathways wherever possible and have observed limited recovery in some regions.
We've streamlined our recovery process to expedite returning the remaining affected servers to service. To further support recovery, we're implementing protective traffic management measures in a specific location to reduce load on the affected infrastructure, and we'll expand these measures to additional locations if we observe positive results. As capacity is restored, users may experience a gradual recovery as their clients reconnect to the service. - 12.11.2026, 23:03 Uhr
We’re continuing to pursue all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief. Our investigation has found that a core process on the affected servers is becoming overwhelmed, which causes the servers to stop responding and contributes to the capacity loss.
To validate a potential recovery approach, we're fully isolating a portion of our service infrastructure, restarting the affected components, and gradually reintroducing traffic to confirm our services remain stable before applying this approach more broadly. We're also analyzing traffic patterns across our entire service infrastructure and evaluating whether isolating traffic within each region may allow affected regions to recover independently. - 12.11.2026, 22:31 Uhr
We're continuing to work through restarting and validating the affected servers to safely return them to service, and we're exploring opportunities to expedite this process. In parallel, we're assessing whether reverting the small number of recent configuration updates we identified could help accelerate recovery.
- 12.11.2026, 21:57 Uhr
We've validated an alternative health check method on a subset of affected infrastructure, which allowed the servers in that subset to successfully return to service, and we're now applying this change more broadly. We're also preparing an automated recovery process to continually detect and restart unresponsive servers, to help keep them in service while this change progresses. Additionally, our review of recent changes has identified a small number of configuration updates that we're investigating as potential contributors to the issue.
- 12.11.2026, 21:38 Uhr
While validating the targeted change, we found that many of the affected servers have become unresponsive, which is preventing us from confirming whether the change is effective. We're restarting these servers so they can come back online with the change in place, and we're applying the same approach to additional affected portions of our infrastructure to validate the results more broadly.
- 12.11.2026, 20:58 Uhr
While we haven't identified any recent changes that correlate with the start of impact, our investigation indicates the failed health checks may originate from a specific component on the affected servers that's responsible for processing them. We're deploying a targeted change to bypass this component on a subset of servers to validate whether this restores availability, and we've taken steps to prevent additional servers from being removed from service while we work to return the affected servers to service. We're also investigating why affected servers are experiencing elevated processor usage while handling requests.
- 12.11.2026, 20:43 Uhr
We've identified that affected servers are failing automated health checks, which is causing them to become unavailable, and this may be related to a recent change to a component involved in processing those checks. We're testing a configuration change on a subset of affected infrastructure to address this and, if successful, will apply it more broadly. In parallel, we've initiated a restart of all affected servers and are validating whether they're successfully returning to service.
This quick update is designed to give the latest information on this issue. - 12.11.2026, 20:30 Uhr
We're aggressively pursuing all pathways to reduce impact. As a precaution, we've paused all deployments and configuration changes while we review recent changes for any correlation to this event. 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.
- 12.11.2026, 19:58 Uhr
We've completed redistributing connection traffic across our worldwide infrastructure, and we're moving additional traffic off the affected infrastructure to further reduce load. We're also restarting affected servers to return them to service. In parallel, we're investigating whether the elevated traffic reflects a genuine increase in requests or a shift in how traffic is being routed across our infrastructure.
- 12.11.2026, 19:27 Uhr
We’re investigating an issue impacting multiple Microsoft 365 services and we've determined the affected infrastructure is experiencing elevated load across multiple regions, which is likely contributing to the connectivity errors. We're restarting and repairing impacted portions of this infrastructure to restore capacity, and reviewing an unexpected increase in a specific type of service traffic to determine whether it's contributing to the elevated load. In parallel, we're evaluating options to redirect traffic to alternate infrastructure to expedite relief.