this is about your pc and your network , try it invite in game while in game press esc and f then press your friend and press i , this is bug you can call your friend or start game and in 5 second call your friends but your friends must wait , remember first of all slow loading a bit second later fast loading , while fast loading your friends must join , if they join in slow loading they take error lost connection to host but if you do my solution so you can be host but there is a problem invite time is 30 second , good luck