How to open a port in ispmanager 4 Lite?

Question

firewall

Hello.
This is the third day I've been trying to find the answer to the question from the title. In the official "help" and various FAQs there is no exact explanation of how exactly to open the port in ispmanager, how their wonderful firewall is configured, and who needs to be sacrificed, this whole wonderful program worked.
Attempts to open the port using iptables, namely the command:
iptables -A INPUT -p tcp --dport 7777 -j ACCEPT
did not work.
The introduction of the rule through the panel did not bring any obvious changes either.
Tools>Firewall>Configure>Create:
Packet Source Address: 0.0.0.0
Rule Priority: 1
Protocol: TCP
Service: Manual
Port: 7777
Action: Accept (ACCEPT))
Waiting for an answer like a nightingale of summer.

Answer 1

Is this port really listening? Show command output:
Also show the list of rules currently in iptables :
All commands must be run as root.

Answer 2

There is a non-zero probability that your server is behind the hoster's firewall, which, of course, is beyond your control - and you need to contact support about opening the port. I had to face this. ISPManager also stood on the server, and I also sinned against him at first.