Microsoft Corp (MSFT  ) faced significant service disruptions on Monday with close to 5,400 people reporting issues with Microsoft 365 on the Down Detector around noon EST.

Around 84% of reports stemmed from Outlook, 10% from Exchange, and 6% from Sharepoint.

Close to 8,500 users reported issues with Microsoft Outlook as per Down Detector, with 67% of problems corresponding to the website, 22% with the app, and 11% with login issues.

Over 300 users reported issues associated with Microsoft Teams on the Down Detector, with 61% of the problems related to the server connection, 26% to the website, and 13% to the website.

Microsoft tweeted at 4:06 am ET that users faced issues with Exchange Online and Microsoft Teams calendars.

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.

At 9:03 am ET, the company tweeted that it had deployed a fix progressing through the affected environment. At the same time, it began a manual restart on a subset of affected machines.

At 12:25 pm ET, the company tweeted that targeted restarts were progressing slower than anticipated for most affected users.

At 5:59 pm ET Tuesday, it tweeted incremental recovery for some users and focused on additional workstreams to resolve all customers' issues.

Microsoft's current status says users may be unable to access or use some of Microsoft 365's services and features.

OpenAI ChatGPT services also experienced disruption on Monday. Users flagged elevated errors on ChatGPT and API from 1:20 pm ET. ChatGPT recovered by 2:55 pm ET, and API performance was recovered for most customers by 4:30 pm ET. The number of issues reported crossed 2,100 on Monday as per Down Detector.

Price Action: Microsoft stock is down 0.33% at $417.40 premarket at last check Tuesday.