Outage alert ยท 13 November 2026
Microsoft 365 outage: Outlook, Exchange Online and Teams down. What happened and what your business should do
On Thursday 12 November 2026, just after 11 a.m. Eastern, businesses across the Americas lost access to their Outlook mailboxes. Within hours the problem had spread around the world and pulled in Teams, SharePoint, Copilot and more. More than half a day later, Microsoft was still bringing servers back a few at a time. Here is what is down, what Microsoft says caused it, and what to do while your email is out.
Key takeaways
- It is Microsoft, not you. Exchange Online is the core of the problem. Do not reset passwords or reinstall Outlook.
- Your mail is very likely safe. This is a problem reaching mailboxes, not losing them. Expect late deliveries and some bounces.
- The cause is not confirmed. Microsoft says servers failed health checks and dropped out, overloading the rest. Traffic did not spike.
- Watch for phishing. Scammers use outages to send fake "sign in again" messages.
- Make a plan for next time: a second way to reach staff and customers, and a backup of Microsoft 365 that sits outside Microsoft.
What is down
Microsoft tracks this under two incidents in the Microsoft 365 admin center: EX1550543 for Exchange Online and MO1550821 for the wider Microsoft 365 impact. Both were listed as service degradations. Microsoft's first notice said users in the Americas "may be unable to connect to their mailboxes in Exchange Online through multiple connection methods". It later warned the issue could affect Microsoft 365 connectivity in any region.
Because so many Microsoft 365 apps lean on Exchange Online for mail, calendars and identity data, the damage spread well beyond email:
| Service | What users saw |
|---|---|
| Outlook and Exchange Online | Mailboxes would not load in Outlook on the web, desktop and mobile. Delayed delivery and a backlog as servers returned. |
| Microsoft Teams | Core chat and meetings largely worked, but calendars and meeting scheduling were affected. Microsoft's first alert was about Teams in North America. |
| SharePoint Online and OneDrive | SharePoint was listed by Microsoft as potentially affected, and users also reported OneDrive problems. Some recently used files would not open from Microsoft 365 apps. |
| Microsoft 365 Copilot | Chat failed to load or answer, and could not reach work email, calendar or files. |
| Defender XDR, Intune, Purview | Listed as affected. Some admin and security portal pages failed to load. |
| Planner, To Do, Power BI and others | Reported as affected, along with parts of Microsoft Graph, Fabric, Universal Print and Windows 365. |
Features that do not depend on Exchange Online were reported to keep working. The knock-on effects reached outside Microsoft, too. OpenAI and Anthropic both reported problems with their Microsoft 365 connectors, and some Google Workspace users who read their mail in the Outlook app had trouble as well.
Who was hit
The outage started in the Americas during the Thursday working day and rolled into Asia-Pacific overnight. Downdetector logged reports from users in 74 countries. In Australia, where it hit on Friday morning, Service NSW asked customers to delay in-person visits, and a government spokesperson said the National Cyber Security Coordinator was aware of the outage and looking into it. In the US, Michigan's state government reported email problems, and at least one listed company, Workhorse Group, moved its quarterly results announcement.
Timeline so far
What Microsoft says caused it
Microsoft has not published a root cause. Its updates through the day tell this story:
- It first blamed "elevated load across multiple regions" and began spreading connection traffic across its wider worldwide infrastructure.
- It then corrected itself: overall traffic had not increased. The load came from "a number of servers being unexpectedly unavailable", which left the remaining servers carrying everything.
- The missing servers were failing automated health checks. Microsoft said the failures might come from the component that processes those checks, and it was also looking at high processor use on the affected servers.
- It said a core process on the affected servers, reported as the one that sets up secure connections, was becoming overwhelmed and the servers stopped answering requests.
To fix it, Microsoft paused all deployments and configuration changes, tested a bypass and then an alternative health-check method, restarted affected servers, and considered rolling back a handful of recent configuration changes. Several of those steps "are not taking as expected", in Microsoft's words. Restored servers "can become unresponsive again once they begin receiving traffic", so Microsoft has been limiting which kinds of traffic reach them and letting users back in gradually.
Microsoft said there was no indication of a cyberattack. Two days earlier it had shipped a record Patch Tuesday that included an exploited Outlook flaw, but Microsoft has not linked the two, and there is no evidence they are connected.
What to do right now
1. Confirm it is Microsoft before you touch anything
Check the Microsoft 365 admin center > Health > Service health for EX1550543 and MO1550821. If you cannot get into the admin center, check status.cloud.microsoft or the @MSFT365Status account on X. If your incident is listed, the fix is on Microsoft's side.
2. Do not "fix" healthy computers
Resetting passwords, rebuilding Outlook profiles or reinstalling Office will not help. It can leave staff locked out or re-downloading whole mailboxes once service returns. Tell staff to wait, and to leave Outlook closed or open as they like.
3. Use what still works
- Outlook desktop in Cached Exchange Mode keeps a local copy of recent mail, calendars and contacts. Staff can usually still read and search what had already downloaded.
- Move urgent conversations to phone, text or a non-Microsoft channel you already use. Do not sign people up for a new tool in a hurry.
- If you run a Microsoft 365 backup outside Microsoft, its portal may let you find and export an important email or attachment from the backup copy, even while Exchange Online is out.
4. Tell customers and suppliers
Post a short note on your website and social accounts: "Our email is affected by the Microsoft 365 outage. For anything urgent, call us on ...". Customers who get bounces or no reply will otherwise assume you are ignoring them.
5. Expect phishing
Every big outage brings fake "Microsoft outage: verify your account" emails and texts. Remind staff that Microsoft will not ask them to sign in through a link to restore their mailbox. Keep multi-factor authentication on and report anything suspicious.
6. When mail comes back, check what you missed
- Microsoft has reported delivery delays and a backlog, so mail may trickle in for hours.
- Look for bounce notices on mail you sent during the outage, and resend anything that matters.
- Ask key customers and suppliers to resend urgent messages, especially orders, invoices and payment changes.
- Write down how long you were without email and what it cost. That number is the start of a real recovery time objective.
An outage is not data loss. But it shows where your gaps are.
Microsoft's uptime promise does not cover your business
Microsoft runs Exchange Online very reliably most of the time, and this outage does not appear to have destroyed anyone's data. But a service credit after the fact does not answer your customers today. Your business is still responsible for how it keeps working when a supplier, even Microsoft, has a bad day. Big cloud outages are no longer rare. We covered two earlier ones in two cloud outages in three weeks: where does your backup live?
Availability and backup are different problems
An outage like this one is about availability: you cannot get to your mail. A deleted mailbox, a ransomware attack on OneDrive or an employee who wipes a folder on the way out is about data: it is gone. Microsoft's built-in retention helps with some of that, but it is not a separate copy you control. That is why we recommend a backup of Microsoft 365 stored outside Microsoft, tested by actually restoring from it.
Plan for a day without email
A simple email continuity plan fits on one page:
- Who decides that "email is down" and tells staff and customers.
- A second channel for staff (phone tree, SMS or a group chat outside Microsoft 365).
- Up-to-date phone numbers for your top customers and suppliers, stored somewhere other than Outlook.
- An off-Microsoft backup of mailboxes, OneDrive and SharePoint, with a tested way to find one email fast.
- A short list of the business processes that stop without email, such as quotes, orders and payroll approvals, and the workaround for each.
If you could not answer those questions on Thursday, this outage was a free rehearsal. The next one may last longer, or land at month-end.
Frequently asked questions
Is Outlook down right now?
As of early 13 November 2026 (UTC), Microsoft was still working on the outage. Some servers and some regions had recovered, but Microsoft had not declared it resolved or given a time for full recovery. Check the Microsoft 365 admin center under Service health (incidents EX1550543 and MO1550821), status.cloud.microsoft or the @MSFT365Status account on X for the latest.
What caused the Microsoft 365 outage?
Microsoft has not published a root cause yet. It said a number of servers unexpectedly became unavailable after failing automated health checks, a core process on those servers became overwhelmed, and the remaining servers were left carrying the load. Microsoft said overall traffic had not increased.
Was it a cyberattack?
Microsoft said there was no indication of a cyberattack, and its service advisories did not report malicious activity.
Is my email lost?
Nothing Microsoft has published suggests mailbox data was lost. This was a problem reaching mailboxes, not deleting them. Mail already stored in your mailbox should be there when access returns.
Will emails sent to us during the outage arrive?
Microsoft reported delayed email delivery and a backlog as servers came back. Sending mail servers normally retry for some time, so most messages should arrive late rather than never. Some may bounce, so check for bounce notices and ask key customers and suppliers to resend anything urgent.
Should we reset passwords or reinstall Outlook?
No. The fault is on Microsoft's side. Resetting passwords, rebuilding Outlook profiles or reinstalling Office will not help and can cause new problems. Be wary of emails or calls asking staff to log in again because of the outage.
Which Microsoft services were affected?
Exchange Online and Outlook were hit hardest. Microsoft also listed Teams, SharePoint Online, Microsoft 365 Copilot and Defender XDR, and reports included Planner, To Do, Intune, Purview and Power BI. Features that do not depend on Exchange Online were reported to keep working.
Would your business have kept working on Thursday?
We help small and mid-size businesses in Ontario, across Canada and in the United States make sure that when Microsoft 365, a server or a ransomware attack takes something away, there is a tested way to get it back.
- Microsoft 365 backup: mailboxes, OneDrive, SharePoint and Teams backed up outside Microsoft, with restores we test.
- Disaster recovery planning: a one-page plan for a day without email, plus recovery targets for your critical systems.
- Recovery readiness check: a quick look at what would stop, and for how long, if your main systems went down tomorrow.
Sources
- Microsoft 365 Service status
- Microsoft 365 Status on X (@MSFT365Status)
- SecurityWeek: Microsoft 365 outage disrupts Outlook, Exchange Online and Teams
- TechRadar: Microsoft Outlook is down for many, live updates
- Tom's Guide: Outlook, Microsoft 365, Teams and more down, live updates
- Digital Trends: Outlook is out, but it's finally restoring slowly
- The Deep Dive: Outlook outage cause remains unknown as restored servers fail again
- The National: Microsoft continuing to work on problem with partial recovery
- Business Standard: Microsoft 365 outage continues with limited recovery
- ABC News (Australia): Microsoft outage drags on for hours
- Forbes Australia: Outlook and Teams still down as fixes stall
- ABC7: Microsoft outage live updates
This article reflects public information as of 13 November 2026, 05:45 UTC (12:45 a.m. Eastern). The outage was still in progress at that time. Downdetector figures are user reports, not a count of affected customers. Check Microsoft's Service health page for the current status; we will update this page when Microsoft publishes its root cause.