Microsoft said Thursday that it was working to resolve technical issues that were getting in the way of people sending and receiving email messages in its Outlook application.

Microsoft Outage Status Update: Problem Identified Amid 451 4.3.2 Temporary Server Issue, Estimated Time Here

Microsoft 365 services including Outlook, Microsoft Defender and Microsoft Purview were impacted on Thursday, with the company issuing an update on the matter.

Microsoft shared a temporary workaround for customers experiencing Outlook freezes after installing this month's Windows security updates.

Why is Microsoft 365 not working and which services and apps are down? Microsoft 365 faced an outage on Thursday affecting Outlook, Teams, Defender, Purview, and Store. Users reported the ‘451 4.3.2 Temporary server error’.

Microsoft has confirmed that the Windows 11 January 2026 Update is causing at least three major issues, rolling out fixes for two bugs.