Updated Friday, November 13, 2026, 12:00 p.m. CST. We'll update this post as Microsoft does.
Microsoft 365 began experiencing issues at 16:17 UTC on Thursday, November 12. As of this update, Microsoft reports encouraging recovery progress but has not declared the incident resolved, and some users may still encounter intermittent issues. If Outlook won't connect, your mail is arriving late, Copilot isn't responding, or your Teams calendar won't load, you're not imagining it, and it isn't your network.
We're in it alongside you. Our email has been unreliable since Thursday morning. This isn't a post about how we saw it coming. It's the information we'd want if we were on your side of it.
Where to get the authoritative word
Microsoft is tracking this as incident MO1550821 (Microsoft 365), with Exchange Online under its own ID, EX1550543. If you have admin access, search for those IDs under Health > Service health in the Microsoft 365 admin center. That's where Microsoft posts its detailed updates first. If you can't get into the admin center, Microsoft's public status page (status.cloud.microsoft) and the @MSFT365Status account on X carry summary updates.
What's affected
Microsoft's incident notice lists, among others:
- Exchange Online: mailbox access through Outlook on the web, desktop, and mobile, plus delayed mail delivery.
- Microsoft 365 Copilot: Copilot Chat may not load or respond.
- Teams calendar and meeting scheduling. Organizations that use Information Barriers may also have trouble starting new chats.
- Security and compliance: Defender for Office 365 Safe Links, the Defender XDR and Purview portals, and Purview data loss prevention and labeling features.
- Services that depend on Exchange: including parts of Intune, Planner, To Do, and Microsoft Graph mail and calendar calls.
The problem was first reported in the Americas. Microsoft later said users in any region could be affected.
Your mail is delayed, not lost
This is the most reassuring detail in Microsoft's updates, and it's easy to miss. Microsoft reports that mail delivery is delayed and has extended the email timeout window to 48 hours, so queued messages aren't dropped while the backlog clears. Expect a wave of delayed mail as service recovers. If something is time-critical, confirm it via Teams chat or phone rather than resending it.
What still works
Most coverage tells you what's down. This is the half that gets you through the day.
- Teams chat, calls, and meetings are largely functional. Microsoft says Teams' core messaging and online meetings remain largely functional, even as calendar and scheduling are affected. If you can't email someone, Teams is very likely the way to reach them.
- Your SharePoint files are still there. SharePoint appears in the incident because some features depend on Exchange, leading people to assume their documents are unavailable. Files stored in SharePoint can still be opened. Go directly to the site or library rather than through a link in an email.
What not to do
This is a problem on Microsoft's side, so local fixes won't help and can create new problems once service returns. Don't reinstall Office, delete Outlook profiles, or reset passwords because of this outage.
One security note that's getting missed
Microsoft says Defender for Office 365 Safe Links may be unable to verify URLs clicked in Outlook and Teams right now, and users may encounter errors even on legitimate links.
That matters more than it sounds. Safe Links runs between a link click and the page opening. When it's unreliable, people get used to seeing errors and clicking past them, and that's exactly the habit you don't want on a day when outage-themed phishing is a predictable lure. Everyone is confused and expects things to be broken, which makes a message saying "your mailbox has been suspended, click here to restore access" far more convincing than usual.
So today, treat unexpected links with more caution, not less. If something asks you to sign in to Microsoft again, don't click it; go to the service directly. And if someone on your team gets a message claiming to be from IT about the outage, verify it by voice.
What we're not going to tell you
We're not going to tell you what caused this.
Microsoft has said several servers became unexpectedly unavailable, straining the remaining infrastructure; that the load wasn't driven by increased traffic; and that a process handling secure connections on affected servers became overwhelmed. Its account has developed as the incident has gone on, which is normal: vendors learn what happened while they're still fixing it. Microsoft has also said there is no indication this resulted from malicious or cyber activity.
But no root cause has been published, so any confident explanation you read today, including one from us, would be a guess. When Microsoft publishes its post-incident report, that's the document worth your time.
What to do today
1. Move urgent coordination to Teams chat or phone. Don't wait on email.
2. Open files directly in SharePoint rather than through links in email.
3. Tell your people about Safe Links. One sentence in a team channel is enough.
4. Don't sign in to anything you reached by clicking a link.
5. Don't reinstall, reset, or rebuild anything on your end.
6. If you're an admin, follow MO1550821 and EX1550543 in the admin center, hold non-urgent changes until things stabilize, and save a copy of the incident details. Service health history doesn't stay there forever, and you'll want it for the post-incident review and any service credit claim.
7. Don't open an outage ticket expecting an engineer. Follow the incident in Service health instead.
Should you open a ticket with Microsoft?
Xcelocloud is seeing Microsoft log tickets about the outage itself for tracking only, without assigning an engineer. The actual updates come through the incident in the admin center (MO1550821 and EX1550543), not through your ticket, so an outage ticket won't get you answers faster than Service health will. If you open one anyway, reference both incident IDs.
Service credit requests are a different kind of ticket, and you can submit them now. Microsoft is treating them as requests for review, not automatic approvals, which is why the evidence behind them matters.
Service credits
Microsoft 365 services are covered by Microsoft's financially backed Service Level Agreement for Online Services. Credits aren't applied automatically. They must be claimed, with supporting details, by the deadline set by the SLA. In most cases, you file through the party that bills you for your Microsoft licensing: Microsoft directly, or your Cloud Solution Provider (CSP) partner if you buy through one.
The hard part usually isn't the form. It's the evidence: which services were affected, for which users, and for how long. Since each claim is reviewed, a clear record is what makes the case. If Xcelocloud manages your environment, we'll put that together for you. If we don't, ask us anyway. We'll tell you what to gather and how to file, so you're not working it out on your own.
We're here
If something is broken, contact us at 833.456.6877, whether or not you're a Xcelocloud customer. Our phone lines aren't affected.
Kim Hershey is Director of Product Management at Xcelocloud, where she brings Fortune 500 structure and discipline to the product management team. She holds an MBA and certifications in Scrum Master, Scrum Product Owner, Kellogg Marketing Leadership, PMP-PMI, and Lean Six Sigma Green Belt. She excels in cross-functional leadership, handling complex projects across various technologies and markets. Kim spends her off-time with her family and books. Her favorite authors are George R.R. Martin, Ethan Wharton, and Kazuo Ishiguro.