This is a scheduled windows-2016 brownout

juliensl You probably already figured this out.  I just ran into it today and for me it was associated with 3 release pipelines that didn't get processed.

For me, I needed to go to dev.azure.com, and check each of my releases:

1) click on a release.

2) click on Edit in the upper right corner

3) click on the deploy stage

4) click on Run on agent

5) you should see something like this: 

If your Agent Specification shows vs2017-win2016, you need to change it to one of the newer versions.

(You can just run that fixed release, and it'll take care of the one that failed previously)