DDNS, IP, Port Forwarding, DHCP. All network settings are checked. Then it's down to the browser compatibility to run with manufacture's own CCTV software. Maybe most Chinese manufacture prefer IE over other browser. So the best way is to call the manufacture service support. Telling them the exact problem, they should have more faults recorded in their memo than us working on the ground. Hope this help as different make using different CCTV software. So there's no one solution to all when no fault at all on the networking side. Cheers