This is usually due to a router problem, some sort of incompatible connection between your computer and the network.
I've tried play D2 at school one but it never connects to server, cause there is something in their network that prevents us from playing games.
Quote (Termn8tin_Cobra @ Jul 14 2011 01:23pm)
Try resetting ur router
I've got that multiple times & that always worked to fix it
Also check to make sure ur firewall isn't blocking the Bnet's access & removing "Bnetcache" from ur D2 folder helps a lot with connection issues
Follow this guide on how to remove your "bnetcache" file
http://forums.d2jsp.org/topic.php?t=9510963&f=21