Facepalm: Microsoft is struggling to restore services after a massive outage disrupted Outlook, Teams, and other applications for several hours globally on Thursday. The company says it has "no indication of a cyber-attack," and that it is still trying to get all affected services up and running.
Users started reporting problems with several Microsoft 365 services on Thursday morning, with outage detection website Down Detector receiving nearly 150,000 reports about people being unable to access Word, Excel, PowerPoint, Outlook, Teams, Copilot, and other Microsoft services.
Microsoft confirmed the outage, saying it was looking into reports of "users experiencing issues accessing Exchange Online mailboxes through multiple connection methods." Some time later, the company reported that its server infrastructure was "experiencing elevated load, (which is) likely contributing to the connectivity errors."
– Microsoft 365 Status (@MSFT365Status) November 12, 2026
By the evening, Microsoft was able to restore some services, but more than 10,000 people were still reporting that they could not access some of Microsoft's biggest and most used online services. One of the worst-affected services was Outlook, with users complaining about their inability to send emails or even access their inbox.
Microsoft later stated that it was trying to mitigate connectivity issues by restarting and validating the affected servers to return them to service. It also said that its engineers were assessing whether recent configuration updates were causing the problems and whether reverting them could help accelerate recovery.
Unfortunately, the company has since reported some of the affected servers that were put back into service were becoming "unresponsive again once they receive traffic." Microsoft says it is analyzing diagnostic data from unresponsive servers as part of its investigations, and is also "temporarily limiting which types of traffic can reach the affected infrastructure in some regions."
– Microsoft 365 Status (@MSFT365Status) November 13, 2026
In the last hour, Microsoft once again posted an update, saying the fixes are not working as expected and that some users are still having problems accessing its services. "We're identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances," the company added.
The outage has not only affected general users and global organizations, but also multiple AI companies, including Anthropic and OpenAI. Both reportedly use Microsoft 365 at their offices and have released separate statements, saying they were investigating severe connectivity issues with Microsoft's services, causing some productivity tools to not work as expected.
Microsoft hasn't revealed key details about the outage, but some researchers believe they know exactly what's happening. Mark Gregory, associate professor in the School of Engineering at RMIT University, told The Guardian that the outage is likely affecting the network layer in Microsoft's systems, and is potentially similar to the configuration issue which brought down Optus's network in 2023.
According to Gregory, when some configuration servers face connectivity issues, users are forced to share the smaller pool of servers that are still online. If the outage persists, the live servers often crash from being overloaded, which is apparently exactly what's happening in this case. We'll have to wait for Microsoft to wrap up its investigations to know more.