on_reboot.service - Script On Reboot
   Loaded: loaded (/etc/systemd/system/on_reboot.service; enabled; vendor preset: enabl
   Active: failed (Result: exit-code) since Mon 2018-09-17 20:46:43 +08; 4min 9s ago
  Process: 301 ExecStart=/home/pi/drowsiness-detection/on_reboot.sh (code=exited, statu
 Main PID: 301 (code=exited, status=139)

Sep 17 20:46:00 raspberrypi systemd[1]: Starting Script On Reboot...
Sep 17 20:46:43 raspberrypi on_reboot.sh[301]: Unable to init server: Could not connect
Sep 17 20:46:43 raspberrypi python[655]: cannot open display:
Sep 17 20:46:43 raspberrypi systemd[1]: on_reboot.service: Main process exited, code=ex
Sep 17 20:46:43 raspberrypi systemd[1]: Failed to start Script On Reboot.
Sep 17 20:46:43 raspberrypi systemd[1]: on_reboot.service: Unit entered failed state.
Sep 17 20:46:43 raspberrypi systemd[1]: on_reboot.service: Failed with result 'exit-cod