Error 6003 is an authentication error. It can be caused by a few things: Your account is locked.
You have not confirmed your account using the confirmation link sent to your email after you signed up.
You have already reached your maximum number of connections. For example... The username and password you used to logged in to the application has changed. Try logging out and logging back in.
You can check the status of your account and you number of connections by logging in to the control panel at www.goldenfrog.com/login.