Microsoft struggles to fix huge outage affecting Outlook and Teams
The Microsoft campus in Mountain View, California, US, on Monday, Jan. 26, 2026. Microsoft Corp. is scheduled to release earnings figures on January 28.
Microsoft365, Outlook, Teams and other apps were disrupted for thousands of users for more than nine hours on Thursday and Friday, with Microsoft scrambling to find a solution after initial fixes failed to bring services back online.
A Microsoft spokesperson said the company “had no indication of a cyber-attack”.
Outage website Down Detector showed a spike in Microsoft 365 problems around 1pm ET, with nearly 130,000 reports of issues in 74 countries affecting access to Word, Excel, PowerPoint, Outlook and Teams, as well as enterprise services such as SharePoint and OneDrive. AI assistant Copilot was also affected.
Microsoft has suggested the outage may have been caused by issues with the settings applied to servers responsible for keeping Microsoft 365 up and running. Over the nine hours the outage had been going on at the time of reporting, the company had attempted a number of solutions to bring back services, including rolling back updates and limiting the traffic flowing to affected servers.
Microsoft 365, Outlook, Teams and other apps were disrupted for thousands of users for more than nine hours on Thursday and Friday, with Microsoft scrambling to find a solution after initial fixes failed to bring services back online.
A Microsoft spokesperson said the company “had no indication of a cyber-attack”.
Outage website Down Detector showed a spike in Microsoft 365 problems around 1pm ET, with nearly 130,000 reports of issues in 74 countries affecting access to Word, Excel, PowerPoint, Outlook and Teams, as well as enterprise services such as SharePoint and OneDrive. AI assistant Copilot was also affected.
Microsoft has suggested the outage may have been caused by issues with the settings applied to servers responsible for keeping Microsoft 365 up and running. Over the nine hours the outage had been going at the time of reporting, the company had attempted a number of solutions to bring back services, including rolling back updates and limiting the traffic flowing to affected servers.
Mark Gregory, associate professor in the School of Engineering at RMIT University, said the outage appears to be affecting the network layer in Microsoft’s systems, and was potentially similar to the configuration issue which brought down Optus’s network in 2023.
He said when some of the servers have configuration issues, it means customers are forced to share a smaller pool of servers to access the cloud services.
“If you lose part of that pool, then all of the users are trying to access the remaining servers, and that overloads them. And then they go down.
“And so you end up with a cascading problem. Then it takes time to find the underlying problem, in this case, a misconfiguration in the network layer.”
Gregory said it showed companies should invest more in testing environments for configuration changes before deployment in the live network, and said businesses reliant on cloud services such as Microsoft 365 should have backup options.
“From a global perspective, there is someone somewhere that’s been badly affected by this, and you end up with lost productivity,” he said.
“They’re being left high and dry now … it then becomes important to have an alternative.
“Many people would keep a Gmail account; if their Microsoft goes down, they use Gmail. If Gmail goes down, they use Microsoft.” Earlier, the company said it had “successfully restored” problems related to Microsoft Teams in North America, although some users continued to report connectivity issues.
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