You may get banned on chatroulette.com and that can be for any reason for example 18+ pictures, cussing or any other conditions which were given by chatroulette.

Or use ccleaner program, clean all things (cookies dns past etc). And use proxy. It will allow you change ip. Then retry to go to chat panel.
Try Changing Browser
You may use different browser to enter Chatroulette to unban, it's a method also. Generally that doesn't work so we offer you to reset modem and re-connect to Chatroulette.
Change Proxy
You may change your IP adresses on PC in order to unban, it's a method and sometimes may not work.
Use Different PC
You can use different pc if you have. You'll connect and system will see you such a newcomer.