Might have something to do with your antivirus and firewall settings.
Nothing is more frustrating than discovering you can't play "Neverwinter Nights 2" with your friends. If you experience complications while trying to connect to the online server, your router may be to blame. While largely responsible for communication between multiple computers and a modem, your router is also a built-in firewall that helps protect your network security. While normally a good thing, this can sometimes keep you from enjoying online games with your friends. Fortunately, you can bypass this firewall without compromising your connection.
manual to find the appropriate IP address. Enter "admin" as both the login ID and password when prompted. Find the "Port Forwarding" section on your admin panel. Enter the following values in the "Start" column: 5120, 6500, 6667, 27900, 28900. Enter these values in the "End" column: 5300, 6500, 27900, 28900. Set the "Protocol" as "UDP" or "Both" for every row of port forwarding. Check the "Enable" box for each set, and label the ports so you can easily recall the forwarding information. Save your settings, and then launch "Neverwinter Nights 2." Select "Connect to server," and you will be able to bypass your router's firewall to play online. IP Adress location http://www.ipaddresslocation.org/router-ip-address.php
Neverwinter Nights 2 http://findports.com/article/neverwinter-nights-2