Shortly before the Coronavirus hit the world in early 2020, Microsoft had it's own crisis.
Microsoft was pushing its Teams platform heavily, even running TV commercials during the NFL playoffs.
Then just after 9AM EST on February 3, 2020, it all stopped.
Microsoft let a certificate expire.
Around noon, Teams was mostly back up. Microsoft confirmed the fix was successfully deployed around 4:30PM.
Maybe they should have put a reminder on their Outlook calendar.