Outlook and Teams down? What to do during the Microsoft 365 outage.

Since Thursday evening, many businesses have been unable to get into Outlook, Teams or SharePoint. Microsoft has confirmed a Microsoft 365 outage under incident MO1550821, and says customers in any region may be affected. As of Friday morning, reports say it has not been fully fixed and Microsoft has not given a time for full recovery.

This page sets out what Microsoft has said so far and what to do in your business while it’s sorted. We’ll update it as things change.

What’s affected

Microsoft says the problem started at 18:26 UK time on Thursday 12 November. Its advisory lists Exchange Online (email in Outlook on the web, the desktop app and phones), Teams, SharePoint Online, Microsoft 365 Copilot and Defender XDR. Its status page has since added Planner, To Do, Intune and Defender for Office 365, among others.

Microsoft also says email delivery may be delayed. Mail servers sending to you normally keep retrying for a while, so most delayed messages should arrive once service is back. Anything urgent is still worth chasing by phone.

Is it a cyber attack?

Microsoft hasn’t said so. Its updates describe a process on some of its servers, the one that sets up secure connections, becoming overwhelmed. It says it is reverting a recent network change that lines up with when the problems started. Some servers it brought back on Thursday night went down again once traffic returned, which is why recovery has been slow.

So unless you’re seeing something the outage doesn’t explain, there’s no sign anything has happened to your own accounts.

What to do now

Do	Why
Check Microsoft’s status page at status.cloud.microsoft, or Service health in your Microsoft 365 admin centre	It’s the only reliable source for when things are back. The admin centre is slow too, so try again if it doesn’t load.
Tell your team and key clients by another route	A phone call, a text or a line on your website saves people wondering why you’ve gone quiet.
Treat “sign in again” emails and calls with extra care	Big outages are a gift to scammers. A fake “service restored, confirm your password” email or a caller offering to fix it for you looks very believable today.
Leave your security settings alone	Don’t turn off MFA, reset everyone’s passwords or let anyone remote in to “fix” it. None of that helps with a Microsoft outage.
Keep a list of anything urgent you sent or expected	Once service is back, check those messages arrived and resend if they didn’t.

A note you can send your team

Microsoft 365 is having a worldwide outage, so Outlook, Teams and SharePoint may not work or may be very slow. It isn’t anything we’ve done and our accounts are fine. Please don’t click links in any email asking you to sign in again or confirm your password, and don’t accept calls from anyone offering to fix it. For anything urgent, phone the person instead. We’ll let you know when it’s back.

Once it’s over

An outage like this is a good test of how your business copes when the tools you rely on disappear for a day. It’s worth asking a few questions while it’s fresh. Did everyone know how to reach each other without Teams? Did you have phone numbers for your key clients and suppliers somewhere other than Outlook? Did anyone know where to check whether the problem was yours or Microsoft’s?

Write the answers down. That page is the start of an incident plan, and it will help just as much on the day the problem is something worse.

Sources

• BleepingComputer: Massive Microsoft 365 outage disrupts Outlook, Teams, Copilot worldwide
• ABC7: Microsoft outage live updates (quoting Microsoft’s status updates)
• Fox Business: Microsoft 365 hit by multi-region connectivity outage
• Microsoft service health status