I'm trying to invoke a web service which requires NTLM authentication and am receiving the following response when obtaining the InputStream object

java.io.IOException: Server returned HTTP response code: 500 for URL: http://XXXXXX:XXX/NAV/WS/Interfaces
at sun.net.http://www.protocol.http.HttpURLConn...tion.java:1308)

When I monitor the HTTP request/response I find that the server response is the below:

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<faultcode xmlns:a="urn:microsoft-dynamics-schemas/error">a:System.Net.WebException</faultcode>
<faultstring xml:lang="it-IT">Soap message is invalid!</faultstring>
<string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">Soap message is invalid!</string>

Now I was wondering why I don't see this response instead of the IOException? I've tried checking the getErrorStream() method from HTTPUrlConnection but returns null.

Any help would me most appreciated.