WCF program behaves strangely on one server - why?

Question

I have a simple get list method for sharepoint (SharePointList is a webrefrence to list.asmx).

    /// <summary>
    /// Returns a list of sharepoint lists
    /// </summary>
    /// <returns>A list of sharepoint lists</returns>
    private string GetSharePointLists()
    {     
        StringBuilder stringBuilder = new StringBuilder();
        try
        {

            SharePointList.ListsSoapClient proxy = new SharePointList.ListsSoapClient();
            proxy.ClientCredentials.Windows.ClientCredential = new NetworkCredential();
            XmlElement lists = proxy.GetListCollection();
            var q = from c in lists.ChildNodes.Cast<XmlNode>()
                    select new
                    {
                        DefaultViewUrl = c.Attributes["DefaultViewUrl"].Value,
                        Title = c.Attributes["Title"].Value
                    };

            foreach (var x in q)
            {
                stringBuilder.AppendLine(string.Format("{0} http://REMOVED/{1}", x.Title, x.DefaultViewUrl.Replace(" ", "%20")));
            }
        }
        catch (Exception ex)
        {
            throw new Exception(ex.ToString());
        }
        return stringBuilder.ToString();
    }

It works fine on my dev box. It used to work fine on my test machine as well. Once the test machine was rebuilt I always get this error on proxy.GetListCollection()-

The HTTP request is unauthorized with client authentication scheme 'Ntlm'. The authentication header received from the server was 'NTLM'.

Anyone know what's going on here and how to fix it?

note: This is a crosspost from sharepointoverflow becuase I'm not sure which site this belongs on.

Answer 1

It turns out the 401 access denied message was nothing more than it seemed. The webservice worked on all other machines because they all had permission to sharepoint webservices.

The user the newly rebuilt server connected as did not. I added the user the server runs as to the "People and Groups" with the appropriate permissions and the list ran fine.