If you have recently changed your username or password, you will need to update your email settings.

1. Close the MyStargate Dashboard and make sure your email program is closed too.
2. Double click the My Computer icon on the Desktop, then double click the Internet Connections folder
3. Right click the Stargate icon and select Properties.
4. Click the Email Tab at the top of the window. Note: You may need to scroll through the tabs by clicking the arrows.
5. Reenter your Email username and password.
6. Click Save.

Also, How do I edit my Username and Password in the dialer?