Do you just need ONE camera to replace a dead camera, or are you adding another camera ?
SO, I suspect this is another OEM, and thus not using Dahua APIs for the IP configuration.
SO, they may not have plug and play compatibility for the cameras they currently sell for that NVR.
( or perhaps they do, and it was not verified, or something in the setup changed for newer camera models .. default password is a typical change from older kits to newer kits )
If the NVR can handle ONVIF cameras :
you can just look for a IP PoE camera that matching the resolution the NVR supports, and with some tinkering on the IP settings of the NVR Channel you'll use for the camera and the Camera itself.
( for example a good Hikvision OEM or Dahua OEM IP PoE camera that is ONVIF compatible. Remember ONVIF has various compatibility levels, as do the proprietary protocols - do not expect the more advanced features for cameras to be compatible with an older NVR )
I'd search the forum for "LNK7216" and "LNK7000" and see if we identified the OEM of that kit previous here.
Let's find out who the OEM of the NVR is ..
Find your NVR's MAC address (printed on the serial number sticker underneath or behind the unit, or found under Main Menu > Settings > Network).
we can lookup the MAC address to determine which OEM this is from, then we can find an option that works well enough.