This means that too many people from your host are connected to the network at the same time. You can try different servers on that network, but that probably won't help. If you're on a network (i.e. college, university, work, cybercafe, home network) then there could be too many people connecting at the same time.
This error is summarised on this page
"TOO MANY CONNECTIONS FROM YOUR HOSTNAME
Closing Link (No more connections)
Closing Link (You are only allowed one connection from your host.)
This means you already have one or more connections to the IRC server and you are not allowed more then the current amount of connections from your address or PC. Normally two connections to the same IRC server are allowed. Check and see if you already have a copy of mIRC running with a connection to this server! Also if you are connecting from behind a firewall or proxy (like Internet Connection Sharing) and thus sharing one IP Number(!), the server will see you all as coming from one address! It will refuse access if more people from your place are on this IRC server already, using the same proxy, or if you have more IRC clients running."
There is little you can do except contact the network and enquire further about it - include your IP and hostname whenever you connect, aswell as the times you tried to connect and which server in any emails you send. Check out the network's website, if you don't know the address search Google