Form submission error: content not allowed in prolog

Question

I am trying to send a simple XML document to a third party automatically, the content is an URL encoded XML document, a view is being created using the following code:

            Using client As New WebClient
                Dim reqParm As New NameValueCollection
                reqParm.Add("cxml-urlencoded", sXmlOrderMessage)
                Dim respBytes = client.UploadValues(cXMLSettings.SupplierSetupUrl, "POST", reqParm)
                Dim respBody = (New UTF8Encoding(False).GetString(respBytes))
            End Using

This works and presents the necessary content. XML is built using the XmlTextWriter component, the title of the document is as follows:

    Dim mem As New MemoryStream
    Dim writer As New XmlTextWriter(mem, Encoding.UTF8)

    writer.WriteStartDocument()
    writer.WriteDocType("cXML", Nothing, "http://xml.cXML.org/schemas/cXML/1.1.009/cXML.dtd", Nothing)
    writer.WriteStartElement("cXML")
    writer.WriteAttributeString("payloadID", objCXMLDetails.PayloadID + Request.Url.Host)
    writer.WriteAttributeString("xml:lang", "en-gb")
    writer.WriteAttributeString("timestamp", DateTime.Now.ToString("o"))

After creating the XML, I then use the following to convert it to a string:

    writer.WriteEndDocument()
    writer.Flush()

    Dim reader As New StreamReader(mem)
    mem.Seek(0, SeekOrigin.Begin)

    Return reader.ReadToEnd

This returns a string that I can then encode the URL.

XML return (I only show the title):

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE cXML SYSTEM "http://xml.cXML.org/schemas/cXML/1.1.009/cXML.dtd">
<cXML payloadID="20180305112030.15272.382530855@localhost" xml:lang="en-gb" timestamp="2018-03-05T11:20:30.9962738+00:00">

The problem is that when sending, I get the following error:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE cXML SYSTEM "http://xml.cXML.org/schemas/cXML/1.2.017/cXML.dtd"> -
<cXML timestamp="2018-03-05T08:46:58" payloadID="87f75924-9851-47c5-bd6d-76c723657476">
  -
  <Response>
    <Status text="Not Acceptable org.jdom.input.JDOMParseException: Error on line 1: Content is not allowed in prolog." code="406" />
  </Response>
</cXML>

I tried

• Removing UTF-8 encoding from XmlTextWriter.
• Removing a schema reference defined in DocType.
• - '<' .

.

Answer 1

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