Connecting to external host (not the same LAN)

I am currently trying to set up simple 2 player multiplayer game. This works fine when I am creating the game within my computer and running one time through Editor and another time from the build.
I use NetworkManagerHUD component to display connection dialog:
View attachment 163678
Now, the problems starts when I am sending my build to my friend, who lives in another side of the world and tries to connect to my host, which I running again in Editor. As my friend lives in completely...

Connecting to external host (not the same LAN)