Microsoft Corp said on Monday it was rolling back a recent change to its authentication system after the update caused an access issue that affected thousands of users of its services, including workplace messaging app Teams.
Outage tracking website Downdetector.com showed that more than 9,100 people had reported issues with Teams, while over 1,100 users posted about problems with Office 365.
Microsoft said initial reports indicated that the primary impact was to Teams, but other services, including its Exchange Online email hosting platform, were also impacted.
More than 2,300 people also reported problems with Microsoft's Azure cloud computing services, according to Downdetector.
Downdetector only tracks outages by collating status reports from a series of sources, including user-submitted errors on its platform. The outage might be affecting a larger number of users.