The company kept frustrated users up to date on Twitter, indicating that there was disruption to "multiple Microsoft 365 services". According to Microsoft, the administrators made a change that was believed to have lead to the failure.
A quick reversal of said change didn't solve the problem, meaning the company had to take further steps. More than six hours after first acknowledging the issue, Microsoft confirmed that it had been resolved.
Office, Outlook and Teams should now be usable again, although a handful of users are still reporting issues. The official status page for Office no longer shows any problems, with issues most likely to persist on Outlook.
There's one key piece of advice that Microsoft gave during the failure that all Microsoft 365 users should heed. If you're currently signed to an Office app, Teams or Outlook and become aware of problems with the services, never sign out of them. Under certain circumstances, you can continue to use them, but new registrations and logins are often out of action.
A version of this story was originally published in German on our sister site, PC-Welt. Translation by Anyron Copeman.