For information related to being banned from a server/network, please see this thread. By 'user' it might mean your username/identd - see if this thread has anything of relevance to what you're experiencing.

Clones are multiple connections to a server/network - make sure you're not bringing bot(s) on to the server/network. If you're connecting via a network (i.e. cyber cafe, work, school, college etc.) then it could be too many people are trying to connect to IRC at the same time.