Over the last 2-3 days I have noticed this happening a lot. I would normally just hit the "Back to MENU" button and try again, but it would never work. I would have to completely re-load the game. Last night I hit the "Check connections" red button that popped up, which took me to a screen showing everything was connected. PvP2 worked fine after that.
I don't know if it is a coincidence, but try hitting the "Check connections" button next time this happens to you. Cheers!