Matchmaking immediately cancels

Every time I try to matchmake for something I accept and then it cancels once all 4 have accepted, is there something wrong with matchmaking?

No problem here , done 2 runs Guardian without a problem , im playing on Eu central Neria server !

We are going to get a 1 hr maintentance over here US West

I got disconnected from the game now because we are gonna have the maintenance too , Even though i have been able to do 2 Guardian Raids and 5 abyss dungeons without a problem .