I need my users are redirected to AuthError.aspx page (\"You don\'t have the access to this page\") in the case when they are authenticated but try to access the page that t
1) enable roles (in web.config): (replace 'xxx' with your own values)
2) you need to restrict access to certain areas of your website for specific roles.
I actually answered another question today where I explain how to achieve this.
Here is the link