FireWall Block Bug

Alright, so on one game, I was just playing with my other 2 friends. I was playing as and the game went to the loading screen. So I waited, but there was nothing but black. I ALT + TAB (I have a Windows 8) out of there and exited out. It said something about my firewall blocking it. But there wasn't anything blocked on my firewall. I exited out the client. It took me back to that screen when you leave the game and it says "the game has crashed. Please reconnect.". I reconnected and it still did that. I exited out again and messaged my friend that my game crashed. He said his game crashed too, but he managed to reconnect. I wished him luck on the game and closed the client.