ActionCable - An unauthorized connection attempt was rejected

試著照上課內容做,卻一直跳An unauthorized connection attempt was rejected
上網找了找只有這篇講的可以解決我的問題
但我還不知道原因,先筆記起來

def find_verified_user
      (current_user = env['warden'].user) ? current_user : reject_unauthorized_connection
 end

http://stackoverflow.com/questions/39438568/actioncable-failed-to-upgrade-to-websocket