This is more a question for your streaming server provider, not for us. Setting up streaming in RadioBOSS is merely entering server address, port, and password. If those details are entered correctly, it will connect, otherwise, it shows you an error message.
Your stream hosting company should provide you with the details on how to connect to their servers. I advice you should contact them and ask them about it, or find the details in their control panel. Also make sure that you do not exceed your bitrate limit - e.g. if you try to broadcast at 128 kbps, but your server allows only 96 kbps, then it may refuse the connection.