I get this a lot but it could be numerous things, it could be the fact that the server isn't recognizing your host name or that it just can't push you through to their game, or that the game has already started. I think in this intense its the update though, i haven't gotten my launcher working quite just yet but when i do i'll be sure to tell you.
In the mean time, just try basic host names, such as join123 and if that doesn't work than just time will tell
sorry!