Hi again Volkun, just making this response here since I responded to you with the same in a different thread. It's just a step back so we can see if a more capable device like a desktop/laptop can communicate with our server from your network, to help determine if it is the network or the Arduino itself acting up.
If it is running OS X or Linux, you can run
telnet arduino.mydevices.com 8442
on your command line.
If things are working, it will disconnect you right away, but you'll get a message like "Connected to arduino.mydevices.com" first.
If you're running Windows, you can download PuTTY: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html to make the same test. You'd be looking for these settings:
Once you click 'Open' there, if you get a popup with 'Connection closed by remote host', then your computer is able to communicate with arduino.mydevices.com on port 8442. If you get a blank black window and no popup message, you're blocked for some local reason that we can continue to help you figure out.