AD Membership Connection

I am having a problem connecting using the ActiveDirectory Membership provider.

I define my Connection string as follows:
<add name="ADConn" connectionString="LDAP://BEL-ADC-01.UTVi.local"/>

And then add:

<authentication mode="Forms">
<forms name=".ADAuthCookie" timeout="10" />
</authentication>
<authorization>
<deny users="?" />
<allow users="*"/>
</authorization>
<!--- Active Directory Membership Provider -->
<membership defaultProvider="MyADMembershipProvider">
<providers>
<remove name="AspNetSqlMembershipProvider" />
<add
name="MyAdMembershipProvider"

type="System.Web.Security.ActiveDirectoryMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
connectionStringName="ADConn"
connectionUsername="UTVi\Administrator"
connectionPassword="*********"
applicationName="/ControlPanel"
/>
</providers>

</membership>

However when I try to login to my web app using a simply login form, I always get the error message:
Your login attempt was not successful. Please try again.

Does any one know where I am going wrong?
.