Hi cgunz410,
I was also facing the same issue so we have changed the port 80 (listen port ) becuase we were not getting response back on that port.
So, my suggestion is you can change the public port and send the traffic on port 80.
port forwarding rule
source ip = any , source port= 81 ( for example 81. you can set any free except 80), Dest IP= NVR IP , Dest Port= 80