I have the same issue.
2 cameras (DS-2CD1023G0-I) are connected to POE switch (DS-3E0109P-E/M) and POE switch is connected to my router then another LAN cable is connected to NVR (DS-7616NI-Q2/16P).
I switched camera 1 to Manual and added the IP camera address to 192.168.254.2. But the error...