Tens of thousands of Microsoft Outlook users worldwide were locked out of their accounts late Saturday night following a brief outage, with the tech giant confirming that it had identified and reverted the suspected cause of the disruption.

In a series of posts on X, Microsoft 365, which oversees services such as Outlook, Excel, PowerPoint, and Teams, acknowledged the issue and stated that it was investigating the problem.

"We've identified a potential cause of impact and have reverted the suspected code to alleviate impact," Microsoft said.

The company further stated that it was reviewing available telemetry data and user-provided logs to assess the scale of the disruption.

"Our telemetry indicates that a majority of impacted services are recovering following our change. We’ll keep monitoring until the impact has been resolved for all services," the statement read.

Widespread impact

According to outage monitoring service DownDetector, Microsoft Outlook, Microsoft Exchange, Microsoft Teams, Microsoft 365, and Microsoft Azure were affected, with reports of the issue surfacing around 2 am (IST) on Sunday.

At the peak of the disruption, more than 37,000 users reported being unable to access their Outlook accounts, while 24,000 encountered difficulties logging into Microsoft 365 services. Additionally, around 150 users confirmed that Microsoft Teams was inaccessible.

While Microsoft has not provided details on what caused the outage, disruptions to Outlook services have been a recurring issue in recent months.

Repeated outages in recent years

Microsoft has faced several major service disruptions in the past. In both 2023 and 2024, the company experienced widespread global outages that took hours to resolve.

The most recent significant outage occurred on November 26, 2024, when Outlook and Teams services remained down for over 24 hours before being restored.