Can't find Steam sessions outside Local network

Hello, I am currently coding a multiplayer game that would allow users to host a session for their friends to join with Unreal Engine 5.0.3.

For that purpose, I am using the “Advanced Session” plugin and am creating a Session with one button and joining the session with another one.
I tried using a 2nd computer with a 2nd steam account plugged on the same Wi-Fi and it works perfectly fine, it finds the session and perfectly connects, however whenever I try to do it with my friend over the internet, the game doesn’t manage to find any session at all.

I am not sure to understand here, I’ve read somewhere that I have to port-forward, but I find it simply odd, does steam require any port forwarding to enable sessions ? If so, then is it impossible to create a game that doesn’t require port forwarding ? Or is it something else ?

I am very confused and found very few informations about this online, which is why I come here asking for help :slight_smile:

Thanks to anyone trying to help in advance !