Can't join PvZ GW1 Garden Ops lobbies on PS3

Hello. When I try to go to Garden Ops and search for a game on PS3, I get a message saying "Unable to join a session. Please check your network connection and try again." (As seen in the attachments.)

I tried to use different networks, and it still doesn't let me join. Only Multiplayer works (like Gardens vs Graveyards, Gnome Bomb, etc.)

Also, I can join friends, if they invite me...

I'd appreciate any help. Thanks :)