hi i have a problem
i cant play with my friend dlc dig with friends

i click on the multiplayer button then make a new world without password and then in the game i click in the portal and sed invitatiion to my friend, but nothing happen

i send the invitation or join to her game in the friend list of gog, and nothing happen, the list of servers are empty
i dont know what is wrong
(one time in the invitation list of gog she acepted and a message say: player dont found )

i have to make the portal in single player to play dig with friends?

note: new games without the portal o campaing or in sandbox,
Note: she have windows 7 and i windows 10.. its a problem?
tankyou and really sorry for my bad english