irc.undergroundnews.com should connect without issue, you can also try irc.undergroundnews.net (as its the direct host, all others are cnamed to it)
Be sure you're using an IRC client and are connecting to port 6667 (if you're trying to connect to the SSL port (6666) then be sure you're accepting unsigned certificates).
Additionally you can use the IRC page at: http://www.undergroundnews.com/irc.php
IRC 1/2/3 are all down until further notice, I believe the current one which is online is IRC5.
*Hell hath no fury like a womens anger and damn be the fool who gets in her way*
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