There are several factors that may cause this issue,
1. SD card issue,
We suggest you download the format tool "Guiformat2" to format the SD card as FAT32,
If it still doesn't work, we suggest you try a new card, we recommend you use the SD cards of Samsung, VIOFO high endurance series.
2. Unstable power source.
We suggest you try to connect the camera to your PC, home socket, or external battery.
try both the GPS port or the side port to power the camera.
3. Loose or wrong connection,
Try the short mini cable or car charger cable (if you use hardwire kits in the car).
unplug the rear/interior cam or reconnect them.
4. Faulty cam body itself,
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