When trying to follow these instructions To configure certificate enrollment policy, I receive the following error. The remote endpoint was not reachable. 0x803d0010 (-2143485936) Here are the instruction that I am given In the console tree under Computer Configuration\Policies\Windows Settings\Security Settings, click Public Key Policies. Double-click Certificate Services Client Certificate Enrollment Policy. Click Add to open the Certificate Enrollment Policy Server dialog box. In the Enter enrollment policy server URI box, type or paste the certificate enrollment policy server URI obtained earlier. In the Authentication type list, select the authentication type required by the enrollment policy server. Click Validate, and review the messages in the Certificate enrollment policy server properties area. The Add button is available only when the enrollment policy server URI and authentication type are valid. Click Add.

It is most likely the URI that you are supplying or that https (if you are not using LDAP) is blocked on the firewall. Typically, it is the former. Please, review the downloadable documentation on Certificate Enrollment Web Services: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=1746 If you still have an issue, please, be more specific about the URI that you are supplying. No need to show any organization specific information, just use example.com or contoso.com, but show the rest or your URI. Also, be sure to specify whether you are using Windows, Certificate, or User Name and Password authentication as well, please.