What Did i get banned for?

[Shawnotize]

Someone please help me...Koolio..are you sure you havent banned my username...it says                Disconnected By Server
                                                               
                                                                                                             You Have Been Banned. Reason: You need to use another username!

please help me with this! i want to play on this server! its awsome!

[Ytsen13]

Perhaps your login to minecraft failed, and you clicked play offline. If you're on offline it uses the playername player, which can't be used because it has been banned. Or it can be that you used the playername player before, and that account might have gotten IP-banned instead of just banned. In any case, I  think this happened by accident. Usually you receive a warning before getting banned. I will unban you now, but you might get banned again by Koolio for reasons unknown to me.