Cant connect to TcpListener

I'm reimplementing my old voice chat app (written in C++) in Rust, finished the first version, tested all locally. Now starting to test it on different machines and can't connect to the server. I have 2 PCs in one local network, one is running a server app and the other is running a client app. The TcpStream::connect() just returns 'connection refused'. The server has a firewall rule for the needed port. I know that it should work because I tried exactly the same thing but with my app in C++. I even tried just starting my old C++ server app and TcpStream::connect() to it from a different machine in Rust - it works, but no matter what I can't connect to my Rust server. Moreover, I tried a simple example code from std::net::TcpListener - Rust, and it's also not working.
So, any ideas on how to investigate this?

What ip did you bind the listener to?, just like in the example.

Change it to

yep :), thanks, gotta read about the difference.