I have a Dahua DHI-NVR52A16 16P-4KS2, With 7 cameras all of which have worked fine since I installed them 4 years ago. one of the cameras that is located on a screened in back porch DH-IPC-HDBW44A1EN-AS, started acting funny several months ago, sometimes I could see it on the monitor and online and sometimes it was gone. now its never on, I checked the CAT 5 today and its good. It looks like the software is just not seeing the camera anymore, I have rebooted the system several times. I have never been able to update firmware for the NVR or any cameras.