Microsoft investigates broad 365 outage hitting Outlook, Teams, Copilot worldwide

Microsoft said it was investigating a widespread outage hitting Outlook, Microsoft Teams, and Copilot across Microsoft 365 services on Thursday, Nov. 12, 2026, after users around the world reported connection problems.

Microsoft said the Microsoft 365 incident began Thursday at 1:26 PM ET. The company had already begun looking into Exchange Online mailbox connection problems in the Americas earlier that day. The company said customers in any region might be affected after it first reported Exchange Online issues in the Americas. The company said it had seen no sign of a cyber attack or malicious activity while still looking into what caused the failures.

Microsoft initially pointed to elevated infrastructure load across several regions, then determined the load was not caused by more traffic. Servers instead became unavailable without warning, straining the remaining infrastructure, the company said. “We determined the elevated load isn’t driven by an increase in traffic, but by a number of servers being unexpectedly unavailable,” Microsoft said. Microsoft paused all deployments, redistributed connection traffic worldwide, shifted traffic away from affected systems, and restarted affected servers to restore capacity.

Microsoft said a test of a different health-check method succeeded, letting some affected servers come back online. The company then started rolling out that change more widely while preparing an automated system to locate and restart servers that stop responding. It was also examining heightened processor usage on affected servers. The company was also reviewing several recent configuration updates that might have played a role, though it has not confirmed what caused the outage.

User-submitted complaints on Downdetector topped 130,000 for Outlook near 1:27 p.m. ET, with more than 46,000 for Microsoft 365 and about 3,000 for Teams. Those numbers are not confirmed counts, and Microsoft has not said how many individuals or organizations were affected. Downdetector said complaints spiked Thursday afternoon for Outlook, Microsoft 365, Teams, Copilot, Azure, OneDrive, and the Microsoft Store. BleepingComputer said it received many user reports of problems reaching Microsoft services, including complaints that Outlook was down.

Microsoft said around 4:30 p.m. ET Thursday that progress had been made in restoring affected infrastructure, though it had not announced a confirmed time for full recovery. The outage was still unresolved at publishing time, and incidents EX1550543 and MO1550821 were both classified as service degradation. Under advisory MO1550821, the company said customers might be unable to access Exchange Online, Microsoft Teams, SharePoint Online, Microsoft 365 Copilot, and Microsoft Defender XDR.

The list of potentially affected services also covers SharePoint Online, Microsoft Planner, Microsoft To Do, and Microsoft Purview capabilities including data loss prevention and communication compliance. The company said it has not established that all listed services face the same level of disruption, and impact could vary by application, connection method, region, and organization. Microsoft named Outlook on the web, MAPI, Exchange ActiveSync, and REST APIs as Exchange Online connection methods that could be affected by the outage.

Microsoft said using Outlook on the web instead of the desktop app may not fix the problem. The company told administrators to watch incidents EX1550543 and MO1550821 through the Microsoft 365 admin center. The company told admins not to make unnecessary configuration changes, saying that reinstalling Outlook or altering local email settings probably will not fix the underlying infrastructure issue. The company advised organizations to rely on alternative communication channels such as independent messaging services or phone calls for urgent work.

A separate Teams incident, tracked as TM1550488, affected users in North and South America from 9:45 AM to 10:53 AM ET Thursday. The earlier Teams outage caused failed message sends, errors when creating or updating conversations, and difficulty fetching chat messages. The earlier Teams outage resulted from resource contention within Microsoft’s infrastructure, the company said, and the issue is now completely fixed. Whether the earlier Teams incident and the broader Microsoft 365 outage are related remains unstated by the company.

Users of Google Workspace reported problems reaching Google-hosted email through Outlook on desktop and mobile. The outage came after Microsoft’s November Patch Tuesday updates, which arrived two days earlier and covered 1,094 vulnerabilities across its products.

Among the updates was CVE-2026-124194, a spoofing flaw in Outlook that attackers have exploited. The flaw could expose authentication material when someone opens a specially crafted file in an affected Outlook client. Microsoft’s service advisories have not linked that flaw to the Exchange Online outage.

A March disruption involving Outlook and Microsoft 365 preceded this outage, with users reporting login failures and email connectivity problems. A June outage of Microsoft Teams files had demonstrated why organizations should test fallback procedures. It also showed why they should check access to critical files after disruptions. In February, an outage of the Microsoft 365 admin center once kept some IT teams from using the tools they rely on to manage and troubleshoot environments.

A Microsoft outage in January left thousands of people without email for eight hours. The outage disrupted critical business operations across North America. The Associated Press reported that people had trouble loading inboxes and exchanging messages, with some still affected after reports declined from the afternoon peak. The incident raises a business continuity question about depending on one cloud provider for email, collaboration tools, and other critical apps, TechRepublic says, and it demonstrates the value of backup communication channels and recovery plans if a primary cloud platform becomes unavailable.