That message is caused when the IRC client closes the connection to the server without notice, and the server doesn't realise the connection has been terminated. This leaves behind somewhat of a ghost user, which gives the appearance that the client is still connected, even though it isn't. When the server attempts to speak with the client, it realizes the connection no longer exists and it's reset. This causes said user to be removed, giving you the quit message. You should have no problem connecting to IRC, at least not being related to this.
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