I'm now just getting back into Web services after a many year absence and tried creating a simple cXMLHttpTransfer process to send a vendor a small xml file and get a return. I tested the site and the XML I'm sending with Postman and it works as expected but obviously I'm not doing something right with the DF call.

Code:
        Get Create (RefClass(cXmlHttpTransfer)) to hoHttp
        Move "www.VendorSite.com" to sServer
        Move "api/sizesrch" to sFilePath

        Get Create (RefClass(cXMLDOMDocument)) to hoDoc
        Set psDocumentName of hoDoc to "C:\api\MyXML.xml"
        Get LoadXMLDocument of hoDoc to bOk
       
        If (bOk) Begin        
            Get HttpGetXmlString of hoHttp sServer sFilePath hoDoc to sXmlR
            If (sXmlR="")  Send Stop_Box "No document returned" "Error"   
            Send Destroy of hoHttp
        End
But what happens is that I get an error from the vendor in sXmlR that says invalid security which means it isn't reading the XML I'm sending it. The XML contains a "secret" or password node. Again, this works fine in Postman.

What might I be missing?