Hi , I am trying to implement NAP Network Access Protection in a lab environment , I have one DC running server 2008 , another server running all of the other roles Active directory certificate services , Network Policy and access services . I have the client running Vista SP1 configured for health certificate enrollment . I have follwed the document published by Microsoft to set this up and everything tests ok . I have a problem with the client not being able to acquire the certificate from the SUB certificate server I am getting the following error message on the event logs: The Network Access Protection Agent failed to acquire a certificate for the request with the correlation-id {8F1D8F0D-0955-46CC-A43A-07ED4C850FE3} - 2008-04-30 17:47:41.251Z from https://nps1.venetech.com/nondomainhra/hcsrvext.dll. I have looked at Event Id 21 - Certificate Acquisition and deletion document published by Microsoft and it looks like everything is cofigured . Has any one experienced the same situation trying to set this up or any ideas of why this still happens even when everything looks like configured correctly . Thank You