Sorry this is in English, Hopefully you will have Google Translate on your browser
First, make sure all your firewall(s) are Low, off, or in "game mode" with Age of Empires III (and the expansion packs) as an exception.
Second, if you are still experiencing Failed to join, make sure your computer fits the connection requirements to play Age of Empires three, if your connection is too slow, you won't be able to join game rooms.
Third, if you are still getting failed to join, Follow these steps:
For XP, go to Start>Run>cmd
Then type in ipconfig
Write down your default gateway
Open Internet explorer
type in the numbers you used for Default Gateway
Password and user-name are usually admin (and) admin, depending upon if you're technologically, well, skilled, and if you are, you should know your Username and password for the router settings.
Find "exceptions" or "gaming" or something of the sort somewhere on that page.
Type in Age3.exe and for the ports type 2300-2310 UDP and 2300-2310 TCP
Close out of windows Internet Explorer
Restart your computer.
For Vista, go to Start and type cmd in the search bar.
Then type in ipconfig
Write down your default gateway
Open Internet explorer
type in the numbers you used for Default Gateway
Password and user-name are usually admin (and) admin, depending upon if you're technologically, well, skilled, and if you are, you should know your Username and password for the router settings.
Find "exceptions" or "gaming" or something of the sort somewhere on that page.
Type in Age3.exe and for the ports type 2300-2310 UDP and 2300-2310 TCP
Close out of windows Internet Explorer
Restart your computer.
All of the players in a game need to follow these kinds of steps. If the host of the game has a super firewalled/anti-virused up computer on lock down, no one will be able to connect to him, and you will still get the failed to join game message, even though it's not your computer.
Also, some routers are just as dumb as a bucket of water and won't let you open ports.
