I am not sure what is causing it but something on your machine is blocking or not receiving communication from the lobby server.
Best way for me to see if you are even sending messages is if you set the client logLevel to "TRACE"
and post the log after trying to log in.
Since you might not be able to do it via the settings you can modify the client.prefs file in the Forged Alliance Forever in your raining appdata folder. There will be a log level entry you just need to set to TRACE.