There was a windows patch installation scheduled during this weekend. Post-installation we noticed many cara agents along with execution servers were offline in the ROC.
But the status of Nolio services were up in server manager on execution servers.
We had to restart Nolio services followed by cache clean up (see Clean up and Troubleshooting best practices
) to get rid of this issue.
All but one execution server is now available. Why is this one Execution Server still unavailable even after the cleanup? The service is running.