Microsoft 365 Outage Hits Outlook and Teams as Servers Go Offline

File photo from our Surface Laptop 7 review.

Microsoft 365 is experiencing a widespread outage on November 12, leaving some users unable to connect to work email, Teams and other cloud services as Microsoft works to bring affected servers back online.

The company initially reported problems accessing Exchange Online mailboxes in the Americas, but later confirmed that Microsoft 365 connectivity could be affected in any region. That puts Canadian users within the potential scope, although Microsoft has not provided a separate Canadian impact count.

Microsoft’s official service health page lists Exchange Online, Microsoft Teams, SharePoint Online, Microsoft Copilot 365, Microsoft Defender XDR, Microsoft Planner, Microsoft To Do and multiple Microsoft Purview services among the potentially affected services. The incident is labelled a service degradation for Microsoft 365 business and enterprise customers, rather than a confirmed outage affecting every customer.

For people trying to get through the workday, the issue could mean trouble accessing email, collaboration tools or shared files. Exchange Online is the cloud service behind many workplace Outlook mailboxes. Microsoft said the mailbox problems were occurring through multiple connection methods, not just one app.

What is causing the Microsoft 365 outage?

In its ongoing status thread, Microsoft said the strain on its infrastructure was not being caused by a surge in traffic. Instead, some servers had unexpectedly become unavailable, leaving the remaining servers to handle the load.

The company traced its investigation to failed automated health checks, which are used to determine whether servers should remain available. Microsoft said a component that processes those checks may be involved, and initially said it had not identified a recent change that matched the start of the disruption. In its latest update, it said a small number of configuration updates were being investigated as potential contributors, not a confirmed cause.

To reduce the impact, Microsoft said it had paused deployments, redistributed connection traffic across its worldwide infrastructure and begun restarting affected servers. It also took steps to stop additional servers from being removed from service while testing a targeted change to bypass the suspected component.

Is Microsoft 365 back online?

Microsoft had not declared the incident resolved in its public status update at 9:01 p.m. UTC on November 12, or 4:01 p.m. Eastern, but it reported progress. An alternative health-check method had allowed a subset of affected servers to return to service, and the company was applying the change more broadly.

It was also preparing an automated recovery process to detect and restart unresponsive servers, helping keep them available while the change rolls out.

Microsoft had not provided a confirmed restoration time in that update. Its next update was due by 10:30 p.m. UTC, or 5:30 p.m. Eastern.

IT administrators can track the incidents under EX1550543 and MO1550821 in the Microsoft 365 admin centre. Microsoft is also posting updates on its public status page because administrators may be unable to reach the admin centre itself.

Are Outlook, Teams or other Microsoft 365 services working for you in Canada? Let us know what you’re seeing in the comments.

In the meantime, maybe it’s time for an extended coffee break.