Line graphics are overlaid on top of video.
Yours has no video signal.
If you reboot the system does it come back on?
If you don't know how to press multiple buttons to reboot, you can shut down the car and wait for 1-2 hrs and start it up again. If you restart too soon, the reboot is not a full one. It reboots from cache w/ bad status/settings.
If reboot does not fix the issue, you might be facing..
1. bad camera head.
2. bad MID unit.
3. or, bad connection from camera to MID unit.
Try the reboot first.