recently changed Hikvision Cube IP camera's (DS-2CD2412F) port and then after it does not work. I also changed the port forwarding in the router. It works only for 1 to 2 hrs, then it cannot be accessed from LAN or WAN. I have the same problem with default port 80 now. ports are 80, 554, 8000. All other port forwarding for other device in router works good. I tried too many ports. I also changed and tried firmware versions 5.1, 5.2 and 5.3 of the IP camera. but no luck.
It works only (with any http port) for 1 to 2 hrs. after resetting the camera to its factory settings. After resetting port shows open status, but after 1 hr. something it's closed. If I use same port with my other device, it works fine.