Looks like master server currently is out of order.
Until it will be fixed, you can connect to servers manually:
Go to MBII web server list: Movie Battles II Server List
Copy ip and port of server you want to play on.
Launch Movie Battles.
Press Shift + ~ (aka Shift + `).
Type "connect " and press Ctrl + V to paste ip:port you've copied before. Command line will be looking like this: