Microsoft mistake took down Exchange Online and Teams on 2/12/22

Microsoft’s flagship cloudy productivity services are down across the Asia-Pacific region.

“Our initial investigation indicates that there our service infrastructure is performing at a sub-optimal level, resulting in impact to general service functionality” states an advisory time-stamped 12:41PM on December 2.

The incident means customers of Exchange Online may not be able to access the service, send email and/or files, or use what Microsoft described as “General functionality”.

The impact on Teams means:

  • Users may experience issues scheduling/editing meetings and/or live meetings;
  • People Picker/Search function may not work as expected;
  • Users may be unable to search Microsoft Teams;
  • Users may be unable to load the Assignments tab in Microsoft Teams.

Messaging, chat, channels, and other core Teams services appear to be available.

Microsoft appears not to know what’s wrong.


Updated at 22:00 UTC, December 2nd The incident has ended! An update to Microsoft’s incident report time-stamped 2314 on December 2 offers the description of the preliminary root cause:

Processing components were not performing within optimal performance thresholds because of a legacy process that required tokens to be processed on specific components. In isolation this process wasn’t problematic, but combined with the large number of requests, this resulted in resource saturation, causing impact across multiple Microsoft 365 apps

Microsoft tested transitioning away from the problematic legacy process and restarting affected infrastructure.

Which worked, so the company did the same thing in its live environment.

The incident ran for nine hours and 59 minutes, from 1355 UTC on December 1st to 0954 UTC on December 2.


Source: Microsoft mistake took down Exchange Online and Teams • The Register

Robin Edgar

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