Hi All, New to the forum, been reading through your posts trying to find one that matches my issue, there's similar issues but I've not found any exactly the same. I'm upgrading my CCTV, I'm using a Hikvision DS-7616NI-I2-16P NVR, I've got two DS-2CD2385FWD-I/GREY 4k cameras installed and working fine for several weeks now, 3rd camera i've added is a 4k varifocal DS-2CD2H85FWD-IZS, this is where my problems have started, I installed it, plugged it's cable into my NVR and it worked, for approximately one day then it stopped, I took it down and plugged it into the NVR using a short cat6 cable to eliminate the cable ran to the camera's mount on my wall, it didn't work, not only did the NVR not detect the camera but the NVR port had no LEDs light up on it with the camera connected, I've tried several different cables and it still doesn't work (including the cables from my already working cameras). The SADP tool doesn't see the camera but I'm unsure I've set it up correctly. So, spoke to the place I bought the camera from then sent it back to them, they say they detected it using SADP then plugged it into an NVR where it worked for 24hrs, they've now sent me it back saying it's fine and suggesting my NVR is at fault. I've upgraded the NVR to the latest Firmware, factory reset it, made more new cat6 cables etc but again I can't get the camera to work and at no point has the port I plug the camera into on my NVR became active (tried all 16 ports and they work fine with my other two Hikvision cameras). I've got a 12v DC supply which I've used alongside the POE cable on the camera, red LEDs flash above and below the lense with the DC supply connected but I still get no response on the NVR port that the camera's connected to. I'd be certain that I've got a faulty camera but it's already been back to the supplier who say they've tested it and claim it's fine. It definitely worked when I first connected it and I've still got that footage on my NVR hdd, but not now Any suggestions please?