We are unable to connect to an HTTPS server using WebRequest
because of this error message:
The request was aborted: Could not create SSL/TLS secur
The problem you're having is that the aspNet user doesn't have access to the certificate. You have to give access using the winhttpcertcfg.exe
An example on how to set this up is at: http://support.microsoft.com/kb/901183
Under step 2 in more information
EDIT: In more recent versions of IIS, this feature is built in to the certificate manager tool - and can be accessed by right clicking on the certificate and using the option for managing private keys. More details here: https://serverfault.com/questions/131046/how-to-grant-iis-7-5-access-to-a-certificate-in-certificate-store/132791#132791