Dedicated server port not working even when server log says it works.

Hello, I am quite new to networking, so it is possible, that I did something wrong somewhere.
My question is, how can I identify where is problem, when my server log says port is bound and is listening to 7777 and also that session creation is complete?
Problem is when I try my multiplayer game on different networks (all working on LAN). I think there is something with port, because I cannot see it in CMD with netstat and also with online checkers, where it says it is closed.
I read many similar problems on forum, but nothing helped me. According all informations I had set all things right (I think of course).
My local ISP is Starlink so (to avoid VPN solutions, because Starlink is not supporting port forwarding) I tried set the server on AWS (windows server) and configured security rules (inbound, outbound) also in windows firewall, public IP that I can ping from my local PC and also tried run everything as administrator - without success.

I dont know, what to check next. I think I have to see opened port 7777 in “netstat” ports list in CMD in first place, but I dont know what to edit. When I change port in server launch script, the port change, but it wont help anyway.

Somebody any idea please?
Tools: (Win11Pro, UE5.2, VisualStudio2022, AWS EC2 instance with public IP and Windows Server as OS)