There are some issues of IP camera as below.
1. MDVR can not search IP camera successfully.
2. Preview video but no image and recording failed.
3. The MDVR voltage of network port is unstable and the recording is lost.
4. Noise from recording video files.
These issues can be checked by supplying power separately.
Here is the steps how to supply power to IP camera separately
1. Divide network cables into three parts: ACC, GND and for camera.
2. Solder a power terminal as below, 7th 8th for GND, 4th 5th for ACC. I think this cable could be available at the local shops if you want it directly.
3. Therefore, the camera could get the voltage not from MDVR but from other side separately.
4. After all steps. You could check whether the above issues still exist.