I kinda gave up on the developers of this game.... Had this problem for a week now (usually played with friends). They sell this game for more than 12 euros! Yet, they do not fix major problems like this immediately! Even free to play games like League of legends fixes bugs like this within hours. And the developers here get paid and don't fix a serious bug... If they wait till the next patch to fix this bug, I'll honestly be really disappointed. 12 euros for a game that the developers don't care about.... Sorry for being emotional and rude, but you, developers of this game, have to get your head into the game.
First of all, it's ONE developer.
Secondly, "more than 12 euros!", it's literally 13,99€ on Steam...
Thirdly, League of Legends has been around for a LONG time and has a HUGE company behind it.
Please, stop your whining and create a better game if you're so great.
NOW, to the issue.
I'm also experiencing this, it's been happening now and then for the past week or two, however I just had to restart the game like 15 times before the Show invite code button appeared for me while trying to host a game for me and a friend.
I hope you're able to patch this relatively soon, until then I hope I don't get stuck in this loop again and it just takes 1-2 restarts to get it working.
THANK YOU for a GREAT (and CHEAP) game.