As it turned out, the problem was the gateway address on the NVR. It was set to 192.168.50.11 instead of 50.1
Crazy that none of the vendors I spoke to, most especially that of the NVR, managed to come up with the gateway theory. We new the data was getting to the router bc I could view it when on the local wifi. We therefore knew the required port was open. But everyone wanted to blame everyone else as to the reason the data wasn't remotely accessible.