I have an application that is being developed for our Intranet.
Which will require authentication of users that are members in an Active Directory group; TIRES Users, TIRES Super, TIRES Admin.

Additionally, I created three SQL Application Roles, TIREAdminCRUD, TIRESuperRU, TIRESUser, with three distinct passwords.
Each group was given execute right to various stored procedures with the schema as 'dbo'.

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My web.config is:
    <system.web>
        <authentication mode="Windows"/>
        <roleManager enabled="true" defaultProvider="AspNetWindowsTokenRoleProvider"/>
        <authorization>
      <allow users ="TIRES Users, TIRES Super, TIRES Admin"/>
<deny users="?"/>

<add name="TIREConnectionString" connectionString="Data Source=DOMAIN\INSTANCE;Initial Catalog=Tires;Integrated Security=True";providerName="System.Data.SqlClient "/>

The goal of my application is to authenticate each user which I do using the following code:
In my asp.net (VB) Page Load I have the following which is working.

Dim strAdmin As String
strAdmin = " TIRES Admin"

If (Roles.IsUserInRole(strAdmin)) Then
'continue
Else
Response.Redirect(http://tires/home.asp)
End If
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But I am running into a problem when they try to connect to the SQL server; the following error message appears:
Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'.
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How do I now authorize each user based on their assigned AD group to allow the execution of the stored procedures?