below you'll find some information on how to track down connectivity issues when starting the game (translated from the german forum)
Part 1 - Ubisoft Game Launcher
Error: "An internet connection is required to play this game" (game does not start at all)
Your firewall is blocking outgoing connections from UGL -> Allow outgoing connections for UGL.
ZoneAlarm7 is blocking UGL without asking. Deactivating ZoneAlarm does not help. You will have deinstall ZoneAlarm7 and switch to a newer version/different firewall.
PeerGuardian is blocking UGL.
A webfilter (integrated into the firewall or installed separately) is modifying the transimted data.
In some (rare) cases when connecting from networks that require you to use a web-proxy you might have to manually enter it into the Settings.ini of the UGL. [I will add information on how to do that if the problem arises)[/list]
Some basic tests:
Can you reach this website with your browser?
1. Install a telnet client (eg. putty)
2. Open a comand shell and execute
<pre class="ip-ubbcode-code-pre">telnet 188.8.131.52 13000</pre> If this times out your connection is blocked (or the servers are down)
Part 2 - Settlers 7
Error: "Server not available"
If you have changed your password - uncheck "Remember me" in the UGL (hit logout after starting) somtimes it fails to notice the change...(and then wrongly displays "Server not available")
The game cannot establish an outgoing connection on UDP ports 21000-29999 -> Check your firewall settings
On some systems there was an issue with the windows firewall excpetions - try to remove the game from the exceptions, start the game and add a new exception.
Error: Cannot join a session after invite / Multiplayer sessions are not visible <
To successfully host a MP game UDP port 9103 must be opened on your machine & forwarded on your router.
Please consult your router's documentation/the internet/your tech-savy friends/me(last) if you're having problems with this.
You can use a portchecker (like this one) to verify that your machine is reachable from the outside.