Microsoft Outlook and Teams suffer major outage

Microsoft’s apps, Outlook and Teams, experienced a major outage on Monday (November 25), leaving users across Europe and other regions unable to access critical communication tools. The outage, which began early in the European workday, caused widespread disruptions for businesses relying on the Office 365 suite.

Microsoft’s response

Microsoft first acknowledged the problem in a tweet, stating: "We're investigating an issue impacting users attempting to access Exchange Online or functionality within Microsoft Teams calendar. For more information, please refer to MO941162 in the admin center."

Identifying the cause:

Shortly after, the company identified a system change as the likely cause and began taking corrective measures: “We’ve identified a recent change which we believe has resulted in impact. We've started to revert the change and are investigating what additional actions are required to mitigate the issue.”

Deployment of fixes:

Microsoft deployed a fix to address the issue, while also manually restarting machines in “unhealthy states.” The company updated users: “We’ve started to deploy a fix which is currently progressing through the affected environment. While this progresses, we’re beginning manual restarts on a subset of machines that are in an unhealthy state.”

Progress report:

The fix was reported to have reached the majority of affected users, with Microsoft stating: “Our fix has reached approximately 98% of the affected environments, and our targeted restarts required for mitigation are being performed as quickly as possible.”

Remaining challenges:

Despite progress, the company admitted delays in restoring services for some users: “Our targeted restarts are progressing slower than anticipated for the majority of affected users. An ETA for resolution will be provided as soon as available.”

Widespread impact

The outage left many users unable to communicate with colleagues, particularly as it coincided with the start of the workday in Europe. Frustration quickly spread across social media, with users reporting issues accessing emails and participating in Teams calls.