ip address lost

I have a Flir dnr700. I have a total of 18 Reolink 410w cameras. There are 11 buildings with cameras. My main modem is in Building 2 NVR is in building 1 I have 3 cameras on building 1, all hardwired into NVR via Ethernet cable. All other cameras will be added via p2p’s and switches, back to...

I changed routers, and have lost one camera. I know the mac address and router wont find the ip when I map ip to mac address. Fing, a great andriod app doesnt find it. (it scans the subnet for devices) Im not sure the factory ip, but dont know how to reset it regardless. Any ideas? Its hard...