Please follow these steps to troubleshoot

Please check if the antenna on the camera is loose first.

1) Cover the sensor under lens on the camera to see if the light is lit or not.

If it's bright, it means camera is good.

If it's not, you can connect camera with other power cable.

In the case of determining that camera is not broken.

2)Right-click the mouse>Video manage>Refresh

3) If step 2 does not work

Pls use an Ethernet cable connect the camera to your NVR.

Delete the Ipc disconnect / Authentication failed Channel>Refresh>Match Code

After that you can unplug the Ethernet cable.