Did cyberattack take down Office, Outlook and Teams? Microsoft reveals what happened

A global Microsoft 365 outage has left hundreds of thousands of users without access to their email or work apps. Microsoft Office, Outlook, and Teams have been down for over 11 hours, sparking concerns online about the reason behind this outage.

Users began reporting issues with Microsoft’s suite of work apps around 11:30 pm IST on Thursday night. Downdetector reported nearly 1,30,000 disruptions in Outlook at the time, though the number of new reports has dropped down to roughly 10,000 since. It is a similar story for Microsoft Office and Teams with thousands of users reporting disruptions.

Microsoft’s work apps are used widely globally with the outage impacting businesses, government agencies, schools, and healthcare providers. Indian airline IndiGo and AI companies OpenAI and Anthropic have also been impacted.

But what caused this global outage in one of the world’s most widely used services? Here is what Microsoft has said so far.

Given the recent cybersecurity events, think Black October or the Binance breach, some were worried that Microsoft may have faced a cyberattack. However, Microsoft executive Charles Lamanna put an end to such speculation. “We regret that today’s outages caused disruptions for our customers, and we are working to address the issue,” Lamanna wrote on X. “For now I can confirm that there is no indication this is the result of malicious or cyber activity.” Microsoft says it has not faced a cyberattack. If it was not a breach, then what was the reason? Initially there were rumours over an issue in Amazon Web Services (AWS) being behind the outage. However, AWS later confirmed that it had not faced any disruption. “AWS services have been operating normally, however an unrelated disruption elsewhere on the internet is prompting some inaccurate news reports,” the company said. AWS' statement.

Then what was behind the outage? According to the official Microsoft 365 status page, the outage is linked to a configuration approach. “We're testing a configuration change to address a problem that's causing servers to fail automated health checks and become unavailable,” the company said.

In simpler terms, Microsoft’s health checks ask servers if they are able to take traffic. It is likely that many servers were failing this health check and, as a result, could not handle traffic. As the affected servers went offline, traffic was directed to the remaining infrastructure, overwhelming those machines.

The outage affected multiple Microsoft services. Outlook users were unable to access their mailboxes while some reported being unable to access files in Microsoft’s 365 suite of apps. The Microsoft 365 admin centre also failed to load for some.

Microsoft’s AI tool, Copilot, was also affected. Users online shared that they were unable to use the chatbot or have Copilot access their files. Some have also faced disruptions in using Microsoft Teams.The outage may stay for longer

By 7:30 am on Friday, most remaining problems had been narrowed down to Microsoft Exchange, the email service supporting Outlook. "We are aware and investigating reports of users experiencing issues with Microsoft 365 services, primarily issues with Exchange Online," a Microsoft spokesperson said.

Microsoft initially prepared a configuration change and tested it on a subset of servers before planning a wider rollout and restarts. The company also began reversing a recent network configuration change that coincided with the start of the outage.We're continuing to work on recovering our frontend servers while implementing further traffic optimization actions to improve service stability and increase capacity. A more comprehensive update can be found at MO1550821 in the Microsoft 365 admin center, as well as https://t.co/pYdahqxDv3 if the admin center is not available to you.— Microsoft 365 Status (@MSFT365Status) November 13, 2026

While Microsoft is working on fixing the outage, things may take a bit longer. As per the company, its servers that returned online became unresponsive as traffic resumed, resulting in a slower recovery. “We’ve monitored the status of the changes applied to improve serviceability and confirmed that change is not taking as expected,” the company wrote. “We’re identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances.”

This is not the first time that we have seen a large-scale outage online. The Crowdstrike outage in July 2024 affected nearly 8.5 million Microsoft Windows computers worldwide. Last year, separate outages in AWS and Cloudflare disrupted online traffic for thousands of users online.- EndsAlso Read | Global outage hits Microsoft, Outlook, Teams down for 11 hours; company respondsAlso Read | Microsoft sees positive results to restart as global outage drags on after hoursAlso Read | Microsoft Outlook, Teams down: Hacks people are using to get office work done

Armaan loves to keep an eye on everything happening in the world of tech and AI. You will find him testing new gadgets, exploring the latest LLMs and making sense of the emerging tech. When not working around tech, he will be exploring new music or catching up on motorsport or aviation.