Warning
Use a sudo-capable account, keep shell history for audit, and back up critical paths before changing boot, SSH, or package state.
What you will achieve
Why did the service die? Read the unit log and fix the actual error.
1) Check status and exit reason
systemctl status your-service.service2) Pull recent logs for unit
journalctl -u your-service.service -n 200 --no-pager3) Validate unit file and command paths
systemd-analyze verify /etc/systemd/system/your-service.service