Trouble with connecting/custom server name

[mastermind777]

I'm having trouble connecting to my Subsonic server on Ubuntu from the Android app. It keeps failing to connect. I registered a custom name, but it keeps saying "mastermind777.subsonic.org is registered, but could not connect to it. (ConnectTimeoutException)". I tried changing it to mastermind7771.subsonic.org, but that didn't work either. The custom server works fine in Windows; the problem is only happening to me on Ubuntu 10.04 right now.

EDIT: I can access the custom URL from my computer, but not through the Android app. The app keeps saying "Connection failure. A network error occured. Please check the server address or try again later."

EDIT 2: Also, it still doesn't connect for some reason even when I use the default URL.