Nakoukl jsem do FAQ a bylo tam tohle:

I can't connect to any rooms! It gets stuck at the "Connecting to host" phase.

If you're experiencing problems connecting to host then you are one of the unfortunate few people who have evil routers.

The reason you have this problem is because the NAT hole punching tech used to make P2P connections in Flash is not compatible with your network topology. This is not a problem with the game, it is a problem with Flash, there is nothing the dev can do about it.

Players have reported a few ways to solve this problem:

Forwarding all the UDP ports in the range 1024..65535 (a lot I know, Flash will pick one at random from that range).
If you are behind two routers enable UPnP in the first one.
Configure your router to point to your computer as a DMZ host.
Removing your router from the equation entirely and connect directly to the internet.
If you are unable to enact the above fixes, don't worry, there are some hosts that you will always be able to connect to, make sure to try every game available. You will be able to connect to at least one of them.

If you find any method to fix this that isn't mentioned in this FAQ please let us know and we'll add it here.

A jelikož absolutně netuším, co to všechno má znamenat, dovolím si Vás poprosit o radu, jak to zkusit spravit. Děkuji za snahu.