Game breaking bug, literally

I was trying to play with my friend, he doesn't see me in the in-game friends' list but I do. And I try to join him multiple times through in-game friends' list, sometimes I do manage and I see him but he doesn't. Other times it doesn't even let me join. When we finally did manage both join and ready up, only one is put to the countdown lobby, and the one who initially joined the leader's party is stranded in the same lobby. But now you can't ready or unready. It's annoying. I don't even know what steps to tell you because it was messy.

First time ever it has happened to me.

Screenshot is when I, through many clicking and trying to join, finally got into a lobby together. Sadly, he was pulled into the game lobby while I was left. For a while it did say "Joining Match", but it just kind of disappeared. After, he left the lobby since he saw I didn't get in, I wasn't able to ready up, and we parted ways.

We both live in Europe. We both play on Steam, PC. We both can get into games separately. But we cannot play together. Annoying.