Connecting to dedicated server over Wi-Fi

Hi. I am using this oldschool dedicated server guidelines:

And am attempting to host server on one windows machine and connect with another. Both are on the same WI-Fi and as I understand that should work without having to forward or open any ports. One of the machines is a PC with a wi-fi adapter, the other one is a laptop.
I have tried using the address that the server shows in the line ‘I am desktop so and so IP:xxx’ as well as ipconfig ones, and the whatsmyip ones too. None of these work when trying to connect from the other computer. Using the local or ‘I am desktop so and so IP:xxx’ when launching on the same machine works consistently though.
Also I did try forwarding the port 7777 and listening address of the server as well as tried opening firewall port 7777. Nothing works.

Any insights would be very helpful.