Can see IP camera image everywhere but NVR?

Just can work this out.

I have hard wired ZXtech IP camera working many months, stopped seeing image via NVR(ZXTech)

I can see image on IE and Onvifer just not on NVR

I have changed IP address same result
Changed resolution on cam software & NVR several times no change
Changed Streams, Changed Frame Rates, switched everything on and off (apart from router & switch), changed stuff I dont know what it does.
IPs all outside DHCP range

I dont know where to go now. All other cameras (3) fine...

Can see IP camera image everywhere but NVR?