Microsoft 365 outage Nov 12: Outlook, Teams, Copilot go down

On Thursday, a Microsoft 365 outage locked business and consumer users out of Outlook. Microsoft also listed Teams, SharePoint, Copilot and Defender XDR as unavailable or affected. It is the second major Microsoft 365 outage since September. If your sales, support and approvals all run through one tenant, today was a free fire drill. Use it.

What actually happened

TechCrunch reported that the problem first showed up in the U.S. and the Americas and then spread to "any region." Its own email was down when it published. The Microsoft 365 admin center was also unreachable at that point, so admins lost the normal place to read incident updates.

Microsoft's explanation changed during the day. Per ABC News, Microsoft first said users could not reach Exchange Online mailboxes through multiple connection methods, and blamed elevated load. It later said the load did not come from more traffic. A number of servers were unexpectedly unavailable, and that put strain on the rest. Microsoft said it had paused all deployments, was moving traffic off the affected infrastructure, and was restarting servers. It reported that Teams in North America was back to normal. At the time of writing, neither outlet reported that Exchange Online was fully restored, and Microsoft had not given a root cause.

TechCrunch notes that the last major incident was in September, a days-long Microsoft 365 outage that Microsoft blamed on a core authentication configuration problem.

Why a Microsoft 365 outage is your problem to plan for

You can't fix Microsoft's servers. You can decide what your business does in the first hour when email stops.

Here is the short list we give clients:

1. A status channel that isn't Microsoft. A shared SMS thread, a Slack workspace, or a phone tree. When Teams and Outlook are down together, "check Teams" is not a plan.
2. Know what dies with Exchange. Order confirmations, password resets, invoice sends, supplier POs. Many small businesses send all of these through one Microsoft mailbox and only find out during an outage.
3. Separate transactional mail. Send receipts and alerts through a dedicated provider (Postmark, SES, Resend) on its own subdomain. Your store keeps working when your inbox doesn't.
4. Queue, don't drop. Any automation that sends through Microsoft Graph or SMTP should retry with backoff and log failures, not fail without notice.
5. Bookmark the status feed. When the admin center is down, Microsoft posts on its @MSFT365Status account on X. Write that into the runbook now.

Sources: TechCrunch, ABC News.