The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.

The self-hosted runner: arc-runner-set-7vkwv-runner-87mgb lost communication with the server. Verify the machine is running and has a healthy network connection. Anything in your workflow that terminates the runner process, starves it for CPU/Memory, or blocks its network access can cause this error.