This is mostly like caused by a faulty or incompatible card,
Step 1: format the card accordingly or use a new one.
Click here to get format instructions.
Below are the cards we recommend,
Step 2: In case the issue persists,
Please reset the cam and update the firmware,
If it fails through all trials,
We suspect the front cam is defective, please contact VIOFO after-sale support to apply for a replacement.
By email address: email@example.com
By opening a ticket: https://support.viofo.com/support/tickets/new