Hi garpu, thanks for answering, yes, that is way I can logging identifying my username, because I've already registered it by
/msg NickServ REGISTER, and no slackware channel is listed. Given your message, I understand you can see it and the problem is on my side and not related to the existence of the channel.
Solved: Apparently something related to the server URL and port. Changed port and now I can see the Slackware channel. Thanks