Unity Network objects only work on local internet??

I have tried many multiplayer sources. pun2free,... until now, netcode for gameobjects. the official unity multiplayer thing I think. So the problem.. it works perfectly fine in my own internet, at the same pc, if I open the game twice, one host and one client. but.... here's the catch: if i open my game with host on my pc, and a other guy, which is in a different internet and pc, I dont show up. like nobody would play. do I have to set th up? did I miss sth? please help!

2 games in my pc working without any issues


when I want to play with some friend not in my internet:

he just doesnt show up.