Outlook down but Teams chat up? The Microsoft workarounds that kept some offices running

Microsoft 365 users were hit with widespread disruption on 12th and 13th November, with issues in Exchange Online impacting access to email and other services. For many businesses, that meant delayed messages, unavailable mailboxes, and disrupted calendars. However, not every MS service went down. Teams chats and calls remained available, so at least some offices could keep in touch. Here's what happened, what services continued to work and what you can do if Microsoft 365 goes down. The information is taken from MQTec GmbH.

Why is Outlook still down?

Microsoft have been tracking the disruption under two incident numbers: EX1550543 for the Exchange Online incident and MO1550821 for the services impacted by the wider issue.

First report at 17:17 CEST on Thursday 12th November. Users were having difficulty accessing their Exchange Online mailboxes initially in the Americas and then more widely across other regions. By 19:26, Microsoft had opened a wider incident. Teams, SharePoint Online, Copilot and Defender were all impacted.


But the impact wasn't uniform across all services. As per Microsoft's update, Teams chats, calls and meetings were all still working, although calendars, scheduling and invitations were all affected. SharePoint file access was still available; external sharing was problematic. Copilot, To Do and Planner were all unreliable, and some of the Defender and Purview security features were limited.

Microsoft said the servers had unexpectedly gone down, adding further pressure on those still up. They reported seeing no sign of an attack.

What could businesses do whilst Outlook was down?

The whole point of the disruption was to highlight that companies need a communication option that goes beyond email. You could absolutely use Teams chat and Teams calls to get to your colleagues in the workplace. It wouldn't be a sensible long-term plan to rely on Teams exclusively, though.

Microsoft has advised users via its incident updates that the recovery effort involved pausing changes, rerouting traffic and the deployment of a patch for an authentication and routing component.

Companies should not be sending the delayed emails over and over again. They're generally just held for another attempt at delivery. In this instance, Microsoft extended the Exchange Online delivery window to 48 hours.

Other practical things to do would be to check Microsoft's service status page, call the customers, check the urgent deadlines and keep a record of the outage.

Email Backup Options and a Contingency Plan

For smaller businesses, an emergency mailbox with a separate provider can be a simple fallback. For the larger organisation that is very much reliant on email, an email continuity service may be worth considering. Local copies of Outlook and independent backups can help staff get to their existing messages and files.

A second MX record on its own isn't a viable solution, and running a separate Exchange server will just add to the maintenance and security overhead.

A good contingency plan should identify the critical processes, map the technology dependencies of those processes, define acceptable levels of downtime, have alternative ways of communicating, have emergency instructions stored outside of Microsoft 365 and test the plan regularly.