They f'd up 12 days since Microsoft f'd up
Broke 0.5 Vistas Fixed well documented Feb 3, 2020 their #48 worst broke on record

Teams went down because nobody renewed a certificate

Expired authentication certificate knocked Teams offline for hours

↳ caused by Expired authentication certificate (February 2020)

The market's verdict: +10.9% on MSFT in the week after.

Status: Fixed. Working as intended, eventually.

What actually happened

On February 3, 2020, Microsoft Teams went dark for roughly three hours at the start of the workday because an authentication certificate had been allowed to expire. Not a hack, not a surge, not a comet: a renewal date. Microsoft confirmed the cause itself, fixed it the same morning, and the incident became the canonical example that the cloud is mostly someone else's calendar reminders. The certificate has presumably been placed on autopay since.

This one is well documented.

Links

  • Impact
    • CNET (publication)

↳ caused by Expired authentication certificate (February 2020)

Timeline

  • Feb 3, 2020 Fixed Microsoft shipped a fix.