Microsoft is investigating an issue with its Microsoft 365 service and its Teams app, with some users reporting to DownDetector that they are having trouble using services such as Exchange and Outlook.

On social media service According to user reports, the issue appears to be affecting Microsoft users worldwide.

“We have identified a recent change that we believe had an impact. We have begun to roll back the change and are investigating what additional actions are necessary to resolve the issue,” Microsoft added in a subsequent post.

Microsoft 365 is a subscription-based app that bundles services like Word and Excel while offering cloud-based storage, while Teams is mainly used by workplaces for video calls and online chat. Although DownDetector, an online service that tracks technical glitches, had only a few dozen reports of problems with 365 as of Monday morning, users posted on social media that they were experiencing problems with Microsoft services.

The University of Galway “is aware of an issue affecting some Microsoft 365 services including Outlook, Outlook Calendars, Teams etc,” the Irish university’s IT group noted on X. “This is an isolated issue impacting Microsoft 365 customers worldwide. Microsoft is aware and investigating.”

According to DownDetector, reports of outages began around 4 a.m. Eastern Time.

Monday’s issues with Microsoft 365 come after a Major disruption in Julywhen banks, airlines, healthcare systems and other industries that rely on the service were hit by a technical glitch caused by global cybersecurity firm CrowdStrike.

The disruption, which led to thousands of flights and train services being canceled worldwide, led to a number of lawsuits, involving Delta Air Lines sue CrowdStrike and Microsoft about the outage, which shut down and caused the airline’s internal systems chaos for travelers.