Lost entry to Abyssal Dungeon

I got matchmade into a dungeon, with the usual server lag, I got a loading screen, then I was back where I started the matchmaking in city. I got an error in chat: “You are not in an assault group. Sending you back to where you were.” When I wanted to queue back I saw that my weekly is gone.

Server: Thirain
Character: Eryllis


We are apparently a lot in this situation