Can't connect to the DVR remotely, why?

Question

System administration

There is a DHI-XVR4108C video recorder, in the local network you can perfectly connect to it via the web at 192.168.1.202 (all addresses are fictitious). There was a need to connect to it via the web, port forwarding did this way:
eth0 - external network

-A INPUT -p tcp -m tcp --dport 5555 -j ACCEPT
-A FORWARD -p tcp -m tcp -i eth0 --dport 80 -j ACCEPT
-A PREROUTING -p tcp -m tcp -i eth0 --dport 5555 -j DNAT --to-destination 192.168.1.202:80
-A POSTROUTING -o eth0 -j MASQUERADE

After that, we have: by going to the address being out of the office at xxx.xxx.xxx.xxx:5555 , we successfully see the login and password window for the user to enter, but when entering the correct data, we persistently get the answer - login error. The plugin for the browser is installed (if it is not there, then the offer to download it is immediately issued on the login page).
I also noticed that in the settings of the device, in addition to the port for http / https, there are settings for tcp / udp ports, I suspect that you can cling to this device with some kind of program, can you tell me which one?

Answer 1

The question is removed, it was also necessary to forward port 37777