MGI Domain Admin - Security MGI security settings allow you to change the username and password for the domain admin. Server Security To change the username and password, enter a new username, a new password, and a verification of the password, then click the "Save" button. The username and password are both case-sensitive. All new domains inherit the current Server Admin username and password as the Domain Admin username and password. However, changing the Server Admin username and password does not change the Domain Admin username and password of existing domains!