Does the NVR still operate OK?
Can you power a camera externally, connect it to the LAN and change it's IP address to match?
Then in the NVR web GUI Camera Management, change the channel to Manual from Plug&Play and change the IP address to that of the camera and see if it connects.
If so, maybe put the cameras on a PoE switch instead and reconfigure all the NVR IP address settings for the cameras to their LAN addresses.
My 8 camera's are OK , It powers up. Can replay old footage. The POE unit got power . POE unit is cooked . No lights . I need to replace the POE module from NVR. I need to know where I can buy a new module . Thank You for your help