The sshd service failed to start due to syntax error with exit status 255.

Issue

• When restarting or starting the sshd service, sshd service fails to start with 'sshd.service: Main process exited, code=exited, status=255/n/a'

  # systemctl restart sshd
  Job for sshd.service failed because the control process exited with error code.
  See "systemctl status sshd.service" and "journalctl -xe" for details.
  

• The sshd service failed to start

  Dec 18 06:54:19 node-0 systemd[1]: sshd.service: Main process exited, code=exited, status=255/n/a
  Dec 18 06:54:19 node-0 systemd[1]: sshd.service: Failed with result 'exit-code'.
  Dec 18 06:54:19 node-0 systemd[1]: Failed to start OpenSSH server daemon.