UE4 Steam Multiplayer Question

I’m working on a Multiplayer Test Project with my cousin. This is the tutorial we followed.

So far i’m able to Host a Session on my PC, then Find and Join the Session from my Laptop through Steam AND LAN. This is great. I can at least play with myself… ( ͡° ͜ʖ ͡°)

However when my cousin and I try to join each other’s game. We can not find each other’s Session.

We’re thinking that this could be a Private/Public Network setting? We’ve played around with that but it hasn’t work.

I’m not sure where to take this next. Any pointer would help.