Public Sub TestCert() Dim myHTTP as New ServerXMLHTTP60 Dim myURL as String ' Open the connection to the secure server myHTTP.Open "GET", "https://server/finalpath", False ' Attempt to set the correct client certificate ' I have also tried just the friendly name as well as ' LOCAL_MACHINEMycert friendly name' myHTTP.SetOption 3, "CURRENT_USERMycert friendly name" ' Send request fails with "A certificate is required ..." myHTTP.Send End Sub Dim apiConnection As New WinHttp.WinHttpRequest ' Set the authentication settings apiConnection.SetClientCertificate "mycert" apiConnection.Open "Get", "https://localhost:8443", False apiConnection.Send