Microsoft is "investigating an issue" with Outlook and Teams.

The company said the outage was "impacting users attempting to access Exchange Online or functionality within Microsoft Teams calendar."

The issue appears to primarily impact users in Europe.

"We’ve identified a recent change which we believe has resulted in impact," Microsoft said in a status update.

"We've started to revert the change and are investigating what additional actions are required to mitigate the issue. For more information, please refer to MO941162 in the admin center.

"We’ve started to deploy a fix which is currently progressing through the affected environment. While this progresses, we’re beginning manual restarts on a subset of machines that are in an unhealthy state. For more information, please refer to MO941162 in the admin center."

Some users, however, claim that the issue is larger than just Exchange Online and Teams - including Microsoft Purview, Universal Print, Outlook on Desktop, and Dynamics 365.