Microsoft continuing to look into the problem after roll back fails to solve issue.

Microsoft is currently looking into an authentication error hitting its Office 365 systems.

“Starting at approximately 21:25 UTC, a subset of customers in the Azure Public and Azure Government cloud may encounter errors performing authentication operations for a number of Microsoft/Azure services, including access to the Azure Portals,” the company said in a status post.

In another post, the company said users would be unable to access Office.com, Outlook.com, Teams, Power Platform, and Dynamics365.

“Existing customer sessions are not impacted and any user who is logged in to an existing session would be able to continue their sessions,” Microsoft said.

On its Twitter status account, Microsoft said the root cause appeared to be a recent change, and that it had decided to roll the change back.

“We’ve rolled back the change that is likely the source of impact and are monitoring the environment to validate that service is recovering,” the company said, before following up 14 minutes later to say it was not seeing what it expected to see.

“We’re not observing an increase in successful connections after rolling back a recent change. We’re working to evaluate additional mitigation solutions while we investigate the root cause.”