soap - Can't use HTTPS with ServerXMLHTTP object

Question

I am supporting a Classic ASP application that connects to a payment gateway via HTTPS. Up until recently there have been no issues. A few days ago the latest updates were installed on the server (Windows Server 2003) and caused the site to break. A code snippet is below.

Dim oHttp
Dim strResult
Set oHttp = CreateObject("MSXML2.ServerXMLHTTP")
oHttp.setOption(2) = 13056
oHttp.open "POST", SOAP_ENDPOINT, false
oHttp.setRequestHeader "Content-Type", "application/soap+xml; charset=utf-8"
oHttp.setRequestHeader "SOAPAction", SOAP_NS + "/" & SOAP_FUNCTION
oHttp.send SOAP_REQUEST

Below is a dump of the error object :-

Number: -2147012852 Description: A certificate is required to complete client authentication Message: A certificate is required to complete client authentication

At first I thought it was because the Payment Gateway's SSL certificate was not being authenticated or they needed a client certificate. I tested the URL in a browser on the server and it displayed correctly without errors and confirmed that the Payment Gateway server did not require a client certificate.

I am at a loss. All the research I have done has lead me nowhere. I even tried the following found on Stackoverflow :-

Getting XMLHTTP to work with HTTPS

xmlHttp, XML request,asp

The last one stated that a client certificate is required by XMLHTTP even though the server does not need it and pointed to a KB article on how to install one, but that is outdated and does not work.

Answer 1

Try adding oHttp.setOption 2, 13056