Large networks like IRCHighway and some other networks require you to give an identd response based on your location, or because your IP range is a common for botnets that attack these networks. It could also be that the connection between you and the server has stopped (I've seen that message myself too). Your best bet is to open up port 113 on your NAT/firewall/router. In mIRC, Alt+O -> Connect -> Identd -> Enable identd server.
Best of luck.
Last edited by darkex; 03/04/10 03:02 AM.