Okay, since recently there was some discussion about the list (http://xmpp.net/directory.php), there're a lot of dead servers and some of the information isn't current. I sent a pull request myself (https://github.com/stpeter/xmppdotnet/pull/125) to update lightwitch.org's vcard since the link to the website is broken.
Maybe a little passage is in order since the last update is dating 2016.
