I Need Help with Telerik Active Directory Error

I no longer have to authenticate when I move on the site to our production server which is the DMZ using the AD. I always get an “Access Denied” and error page on the line:
- type="Telerik.Security.ActiveDirectory.TelerikADMembershipProvider, Telerik.Security"/>
And I tried changing the LDAP server path, the error message changes to
- "Unable to establish secure connection with the server"
The problem appears to be related to the Telerik Active Directory provider after I got an installation of Sitefinity working with Active Directory login on a development server inside our domain. I will be grateful if you could help me on this.
