How to determine why an agent pool is offline in Azure dev-ops

Question

I noticed that all of my builds suddenly got stuck. If I click the build I get the following error: All eligible agents are disabled or offline

When I check my agent pools I get the following:

How can I bring them online/determine why they are offline?

Answer 1

For me, issue was suddenly agents were reporting offline on the portal.

1. Restarted the agent service in the VM - didn't help
2. Removed config file also didn't help because logs were showing that dev.azure.com wasn't connecting
3. Simply just restarting VM helped, but still couldn't able to find the cause.

Answer 2

Login to powershell.Navigate to the agent folder where it contains run cmd prompt and config cmd prompt.

Execute the following command

.\run.cmd