## The symptom
Azure DevOps pipelines suddenly fail with:
```
A task is missing. The pipeline references a task called AzureAppConfigurationPush
with version 6. This indicates that the specific task version can not be found.
```
It hit versions 5, 6, and 7 across multiple projects with no pipeline changes.
## Why
This was caused by the release of task version 10, which broke resolution of the
older task versions. The Azure team removed version 10 from the marketplace to
restore the previous versions.
## The fix
Revert your pipeline back to the task version you were using before, e.g.
`AzureAppConfigurationPush@6`. Do not stay on v10, and do not treat v10 as the
fix if you upgraded to it as a workaround during the incident: v10 is no longer
published, so switch back.
## The general lesson
When many unrelated pipelines break at once with no changes on your side, check
the marketplace or the task publisher's status before touching your YAML. A
global incident looks exactly like a config error at first.