no video signal on headrest monitor

[Finne]

Hello I bought the following system via Amazon:
PUMPKIN 1 Din Autoradio Moniceiver CD Player 7 Zoll Android 5.1 mit GPS Navi Rückfahrkamera unterstützt Bluetooth Wifi MirrorLink

I installed everything how described in the instruction but I get no video signal on the headrest monitors.
There was a video signal shown only once after installation, but after the second switch on of the system there was no signal anymore.
Any Idea what can be the problem?

Thanks in advance for your help

[Jammy]

Hi,
Your amazon order number would be appreciated.
For the video from unit to headrest monitor, you first need to double check and confirm the RCA audio out/in cable right.
And except the DVD video can show on the headrest monitor even if the unit play other app.
For other video signal, such as Youtube, SD card video, they will only display on the headrest monitor only when the unit play same video at the same time, hope you can understand.
Regards