I have a similar issue where the IRC bot will try to connect to the server and (apparently) timeout:
Sep 2, 2010 8:50:23 AM hudson.plugins.ircbot.v2.IRCConnection connect
INFO: connected to IRC
Sep 2, 2010 8:50:23 AM hudson.plugins.ircbot.v2.IRCConnection getGroupChat
INFO: Trying to join channel #welcome
(never reaches the "Joined channel..." log line)
It seems to be happening at this line (it's nested, so I don't know which constructor is causing it):
// TODO: how to check that join was successful (channelJoined is called later -
// how long should we possibly wait until we declare that join was unsuccessful?)
this.bots.add(new Bot(new IRCChannel(channel.getName(), this.pircConnection),
When I query my OperServ, however, I don't see my bot connected, so I can't invite it as suggested previously. I've tried inviting it anyway, and it won't let me (because it's not connected). Checking my IRC connection logs, I see connections from my users, but not from the Hudson IRC bot. I suppose it's possible that some exception is being thrown during connection but being handled silently.
I've tried connecting with my Chan/NickServ bot offline, to see if maybe it was booting it, and that didn't help. I've tried turning off my NickServ Identify password to just let it join as an unregistered user (my internal IRC doesn't require a registered account).
I can connect to the server as the Hudson IRC bot user with an IRC client, so I know the user and NickServ password are correct. One thing to note is that if I'm connected via a client to the Hudson IRC bot account, and the Hudson plugin tries to connect, it does report that the username is already in use, so I know that a basic connection is being made, but not much more. I'm not really sure what else to check.