Microsoft Outlook Outage: Global Microsoft 365 Failure Hit 74 Countries on November 12–13

November 14, 2026 — Microsoft’s email and productivity services are back to normal this morning after a global outage that began on Thursday, November 12, disrupted Outlook for more than a day, spread to 74 countries and left businesses, governments — including staff of the US House of Representatives — without email. Microsoft has apologised, confirmed the failure was not a cyberattack, and promised a full post-incident report. Here is what happened, in order.

How the outage unfolded

Reports of problems started climbing at around 11:17 a.m. ET on Thursday, November 12, according to outage tracker Downdetector, and exploded within the hour — at the spike, Downdetector was receiving around 19,650 reports a minute across Microsoft’s services, from 74 countries and territories. Outlook reports alone peaked at roughly 130,000 at about 1:15 p.m. ET, more than 2,000 times the normal level, while Microsoft 365 reports passed 50,000.

Microsoft opened an Exchange Online incident, EX1550543, at about 1:26 p.m. ET, saying users in the Americas might be unable to access their mailboxes through Outlook on the web, the desktop app, mobile sync or other connection methods, and that email delivery could be delayed. A wider Microsoft 365 incident, MO1550821, followed as the failure spread well beyond email: Microsoft’s service health page listed Exchange Online, Outlook, Teams, SharePoint Online, OneDrive, Microsoft 365 Copilot, Defender, Planner, To Do, Intune, Purview and Power BI among the services degraded.

Recovery attempts through Thursday evening only partly worked. Microsoft said some servers it brought back became unresponsive again once traffic returned, and by 11:30 p.m. ET more than 18,000 US users were still reporting Outlook problems. The outage ran into a second day: on Friday, November 13, Downdetector still recorded about 11,747 Outlook reports at 7:11 a.m. ET. Numbers then fell steadily — about 1,600 reports by 2:50 p.m. ET — and by around 3 p.m. ET Microsoft’s status page showed its services operational again, with a warning that some people could still see intermittent access problems or delayed email while servers stabilised.

What caused it, according to Microsoft

In an update posted just before 1 p.m. ET on Friday, Microsoft said: “We are deeply sorry for the disruption this incident has caused you and your business… This was a technical issue not related to cyber or AI / agents.” The company said the incident “resulted from an issue during an earlier network capacity upgrade that surfaced following a recent network change.”

The technical picture Microsoft described across its updates: a number of its servers failed automated health checks and became unexpectedly unavailable, which pushed an “elevated load” onto the servers still running; on the affected servers, a process responsible for establishing secure connections became overwhelmed and stopped processing requests. Microsoft rolled back the network change, applied an authentication and routing configuration patch, froze other deployments, and returned servers to service gradually so they would stay stable under returning traffic. By Friday afternoon it said email queues were “significantly reduced and approaching normal levels.” Executive vice-president Charles Lamanna confirmed on Thursday night that there was “no indication” of malicious or cyber activity, and Microsoft says a full Post-Incident Report with the root cause will follow once its review is complete.

Is Outlook back up now?

For almost everyone, yes. Microsoft’s service health page showed services operational from Friday afternoon ET, and report volumes are back near normal. Because Microsoft restored service region by region, a small number of users may still hit intermittent sign-in or syncing problems, and mail sent during the outage window can still arrive late as the last queues clear.

If Outlook is still misbehaving for you, do not start reinstalling things. First run the two-minute check in our guide Is Outlook Down? How to Check in 2 Minutes to confirm whether anything is still down on Microsoft’s side — and if the service is back but your app has not caught up, work through Outlook Still Not Working After the Outage? Reconnect and Catch Up.

Sources: Microsoft statements via Microsoft 365 Status and the Microsoft service health status page, as reported by USA TODAY, “Microsoft services mostly fixed after 24-hour outage” (November 13, 2026) — https://www.usatoday.com/story/tech/2026/11/13/microsoft-outage-outlook-updates-friday/92752697007/ — and Computer Weekly, “Outlook down: Microsoft outage exposes UK’s single point of failure” (November 13, 2026). Outage report figures: Downdetector, as reported in the same coverage.

Still stuck after the outage? Email us at servicedesk@howtofixerroronline.com — we’re available 24 hours.