If SD/TF card format is incorrect, it won't work with device and record video.

Please follow the instructions:
1. Cut off the power of camera. Pull out the sd card.
2. Wait for 2 minutes,
3. Insert the sd card into the camera, then power on camera.
4. Open APP-setting-general-Micro SD card, there you can format it.

 Notes: Format sd card would delete all files, please download all files before formating.