Thanks for using the forums. What kind of device are you trying to connect on? Changing the email and password of the Slingbox wouldn't generally give you an error of connecting to the Slingbox. You may want to log out and log back in using the correct email and password. If that still gives you an error, you would want to reset the Slingbox and go back through the setup at setup.slingbox.com.
The Sling Moderation Team