Is Outlook Down? How to Check Microsoft 365 Status and Read Incident IDs Like EX1550543
"Is Outlook down or is it just me?" is one of the great workplace questions, usually asked out loud to nobody in particular. There is a faster way to settle it than polling the room.
The quick answer: check Microsoft's own status. Administrators use Service health in the Microsoft 365 admin center. Everyone else can use Microsoft's public status page at status.cloud.microsoft, or its Microsoft 365 Status account on X. If Microsoft lists an incident, it is not just you.
How do you check if Outlook is down?
| Where to check | Who can use it | What Microsoft says about it |
|---|---|---|
| Microsoft 365 admin center: Health, then Service health | Administrators | Shows the health of your Microsoft services, with current incidents and advisories |
| status.cloud.microsoft | Anyone | For checking known issues when you cannot sign in to the admin center |
| @MSFT365Status on X | Anyone | Microsoft posts information on certain events here |
One practical note from the November 2026 outage: reporters at Engadget said the public status page itself was slow to load for some of them. If one channel will not open, try the next.
Source: Microsoft Learn, How to check Microsoft 365 service health; Engadget.
Is it Outlook, or is it your internet? A 60-second test
This is SourceIT's own quick test.
- Open two unrelated websites. Microsoft's own support page suggests trying microsoft.com or bing.com. If they load, your internet works.
- Look at the bottom of the Outlook window. Microsoft says that if the status bar shows Disconnected, Working Offline or Trying to connect, Outlook cannot reach the email server.
- Try your phone on mobile data. If mail fails there too, your office network is not the cause.
- Ask one colleague. Two people, same problem, same minute: it is the service.
During the 13 November outage we saw exactly this pattern from a Singapore office: other websites loaded, Microsoft sign-in responded, and the Outlook web addresses timed out. Outlook on the web then announced it "can't reach the internet", which was not the internet's fault.
Source: Microsoft Support, My messages won't send; Microsoft Support, Check if mail server/Outlook is online.
What do the Microsoft status labels mean?
| Status | What it means, paraphrased from Microsoft |
|---|---|
| Investigating | A potential issue is being looked into; the scope is not yet known |
| Service degradation | A confirmed issue that may affect use, such as slowness or intermittent interruptions |
| Service interruption | A confirmed, significant issue that prevents users from accessing the service |
| Restoring service | The cause is identified and corrective action is under way |
| Extended recovery | A fix is reaching most users but still rolling out, or a temporary fix is in place |
| Service restored | Corrective action has resolved the problem |
| Post-incident report published | A report with root cause and next steps is available |
Microsoft also separates an incident, where a service or major function is unavailable, from an advisory, where a problem affects some users but the service is still available.
What do EX1550543 and MO1550821 mean?
They are Microsoft's reference numbers for the November 2026 outage. The letters point to the service and the number identifies the incident. Microsoft's partner documentation lists these prefixes:
| Prefix | Service, as listed in Microsoft's partner documentation |
|---|---|
| EX | Exchange Online |
| FO | Exchange Online Protection |
| SP | SharePoint Online |
| PB | Power BI |
| OS | Office Subscription |
| MO | Listed there as "Portal error". In the November 2026 outage, Microsoft used MO1550821 for the incident covering the wider Microsoft 365 suite |
So EX1550543 is the Exchange Online incident, the one behind Outlook, and MO1550821 is the companion incident for other Microsoft 365 services. You will want both if you later raise the matter with Microsoft. See how to complain to Microsoft about the Outlook outage.
Source: Microsoft Learn, How and when to request a credit from Microsoft.
How do you get told automatically next time?
Administrators can turn on email notifications in Service health: choose Customize, then Email, and enter up to two addresses. For a live incident, select it and choose Manage notifications for this issue.
If you see a problem that Microsoft has not listed, its documentation says to select Report an issue on the Service health page and fill in the short form.
The fastest way to find out whether it is just you is to stop asking the room and ask Microsoft.
More on the Microsoft 365 outage
- Microsoft outage latest update and timeline in Singapore time
- Is Teams down? Which Microsoft 365 services were affected
- What Microsoft has confirmed, and an IT manager checklist
- Outlook not working after the outage: how to fix it
- Microsoft outage history: how often does it go down?
Related products and solutions from SourceIT
Checking the status page tells you whose problem it is. These are for the parts that are yours. None of them prevents a Microsoft-side outage.
| If you want to | Look at |
|---|---|
| Rule out your own office network faster next time | Fortinet FortiGate firewalls for small businesses |
| Keep your own copy of company mailboxes and files | Synology backup and data protection for business |
| Review which Microsoft 365 plan you are on | Microsoft 365 for Business plans |
Getting help in Singapore
For backup and continuity planning, call (65) 6978 3502, email Sales@sourceit.com.sg or use our contact page.
Frequently asked questions
How do I check if Outlook is down? Check Service health in the Microsoft 365 admin center if you are an administrator, or Microsoft's public status page at status.cloud.microsoft.
What does EX1550543 mean? It is Microsoft's incident reference for the Exchange Online part of the November 2026 outage. EX stands for Exchange Online.
What does "service degradation" mean? Microsoft uses it for a confirmed issue that may affect use of a service, such as slowness or intermittent interruptions.
Can I get email alerts for Microsoft 365 outages? Administrators can turn on email notifications in Service health under Customize, then Email.
This article is general information compiled from the Microsoft sources linked above as at 13 November 2026. It is not a statement by or on behalf of Microsoft. Microsoft, Microsoft 365 and Outlook are trademarks of the Microsoft group of companies.
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