Microsoft is investigating an issue with its Microsoft 365 service and Teams app. Some users report to DownDetector that they are having problems using services such as Exchange and Outlook.

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

“We have identified a recent change that we believe has had an impact. We have begun reverting the change and are investigating what additional actions are needed 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 providing cloud-based storage, while Teams is primarily used by workplaces for video calls and online chat. Although there were only a few dozen reports of problems with 365 on DownDetector, an online service that tracks technical outages, as of early Monday morning, users on social media revealed 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 Calendar, Teams, etc.,” the Irish university’s IT group noted to X. “This is an intermittent issue that Microsoft 365 customers worldwide. Microsoft is aware of this and is investigating.”

When did the outage start?

According to DownDetector, reports of outages began around 4 a.m. Eastern Time. As of 10 a.m. there had been about 2,000 reports from people saying they were having problems with Microsoft 365, the outage detection service said.

By midday Eastern Time, reports were up to 5,000 before complaints about DownDetector subsided in the late afternoon. However, as of Monday afternoon, Microsoft users were still posting about errors and problems connecting to the company’s services.

“Unfortunately, this is our primary tool for doing business, so everything is on hold for us until it is resolved,” one user wrote on X around 1 p.m. Eastern Time.

Monday’s problems with Microsoft 365 come after a Massive outage in Julyas banks, airlines, healthcare systems and other industries that rely on the service were hit by a technical issue caused by global cybersecurity company CrowdStrike.

The disruption, which caused thousands of flights and trains to be canceled worldwide, sparked a series of lawsuits at Delta Air Lines sue CrowdStrike and Microsoft about the outage that crippled and caused the airline’s internal systems chaos for travelers.

Is Outlook down?

According to DownDetector, some users reported problems with Microsoft Outlook, including problems connecting to the service and sending emails.

“Outlook 365 is really patchy this morning. There are intermittent email outages,” one user wrote on DownDetector.

Mike Gatto, an attorney at the Actium law firm and a former California congressman, wrote this week.”

Others said they had trouble accessing their OneDrive files, which are documents stored in the cloud.

Has Microsoft released an update?

At 9 a.m. Eastern Time, Microsoft said it was working on a solution to fix the problem, but did not provide a time frame for when its apps would be operational again.

“We have begun deploying a fix, which is currently in progress in the affected environment,” Microsoft wrote on

Shortly before midday, Microsoft said the patch had been deployed to around 98% of “affected environments” and that “our targeted reboots required to limit the damage will be performed as quickly as possible.”

But at 1:51 p.m., the company posted another update on social media, admitting that it was facing “delays” in restoring affected 365 services, frustrating customers.

“We understand the significant impact of this event on your business and are working to provide remediation as quickly as possible,” Microsoft said.