Late Monday night and early Tuesday morning, Microsoft Outlook was unavailable. The Microsoft 365 Status Twitter account posted that the company was “investigating access and service issues for Outlook” at 11:28 p.m. ET. At 12:24am ET, it tweeted, “a recent change is contributing to the cause of impact.” We’re investigating options to make the service available again. Using Downdetector, we can determine that the outage began sometime after 10:30 p.m. ET. The scope of the outage is currently unknown. Requests for comment sent to Microsoft on Tuesday morning went unanswered.