I have the following code that creates a serverside object of the xmlhttp class. I am trying to connect to a site that requires basic authentication. I am able to get this
I believe you're hitting this known limitation (or bug) that can be boiled down to msxml2 lacking (or having incorrect) support for "negotiated" authentication mechanisms, which means you have to force the issue (bypass the incorrectly-conducted negotiation) exactly by adding the authorization header yourself as you're doing.