Oops, answered in the wrong topic for it myself…
Well, from what I saw, sometimes some channels are just dead : when you connect into them from inside the game, things are really wonky before you get disconnected, and when you try to reconnect from outside, you get this message.
Switching channels is enough to avoid it, but if you want a ‘quick fix’ for the lag issues, it should be a good place to start
More channels are always good 
PS : oh, and do the number of channel have an incidence on the capacity of the servers or anything? Just curious, because well, having a 400~queue when there are only two channels open (with one not working) and both are in the white looks a bit strange. (It’s not a complaint or anything, just plain curiosity :P)