User blog comment:Dentface/Release Notes - January 10th - Bug Fixes/@comment-98.220.217.190-20120114133147/@comment-66.129.58.3-20120119015204

That happened to me a long time ago, it turns out my firewall was rejecting it, so every time I played I would have to turn off my firewall, but now it has fixed itself, and I don't have to turn it off anymore and I can just play. I would first trying restoring your computer back to when it started, then if that doesn't work try turning off your firewall :)