Issues with Advanced Sessions Plugin

Advanced Sessions Plugin returns client only "servers " as full and won’t join the multiplayer session even though there is only one person on the server (the host).
I’m using Epic Online Services as a back-end for the plugin and I’ve configured it with the correct client credentials as it lets me log in.

Here are my blueprints for creating, finding and displaying the sessions
And here’s how the server selector looks after creating and finding a session
Pressing the join button results in the game printing the “Successfully joined session” message but nothing happens even after like five minutes of waiting.

Edit: removing EOS and replacing it with the NULL online subsystem resolves the problem but if I try to find servers hosted on a separate pc (on the same LAN) no servers show up. I guess there is something wrong with multi/any-casting on the network. I’ve checked firewall settings and it isn’t blocking communication for the game executable.