GetListItems() causes a 401 error but Checkout() works

Question

Just asked this over on StackOverflow, so I apologize for cross-posting, but I thought I might have more luck with a response on this site.

I want to get the contents of a SharePoint 2007 list via web service. I'm using this code, which I mostly copied from the MSDN page for GetListItems:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;

namespace testGetListItems
{
    class Program
    {
        static void Main(string[] args)
        {
            sharepoint.Lists listService = new sharepoint.Lists();
            listService.Credentials = System.Net.CredentialCache.DefaultCredentials;

            XmlDocument xmlDoc = new System.Xml.XmlDocument();

            XmlNode ndQuery = xmlDoc.CreateNode(XmlNodeType.Element, "Query", "");
            XmlNode ndViewFields = xmlDoc.CreateNode(XmlNodeType.Element, "ViewFields", "");
            XmlNode ndQueryOptions = xmlDoc.CreateNode(XmlNodeType.Element, "QueryOptions", "");

            ndQueryOptions.InnerXml =
                "<IncludeMandatoryColumns>FALSE</IncludeMandatoryColumns>" +
                "<DateInUtc>TRUE</DateInUtc>";
            ndViewFields.InnerXml = "<FieldRef Name='Field1' />    <FieldRef Name='Field2'/>";
            ndQuery.InnerXml = "<Where><And><Gt><FieldRef Name='Field1'/>" +
                "<Value Type='Number'>5000</Value></Gt><Gt><FieldRef Name='Field2'/>" +
                "<Value Type=        'DateTime'>2003-07-03T00:00:00</Value></Gt></And></Where>";
            try
            {
                bool checkoutResult=listService.CheckOutFile("http://sharepoint/sites/mysite/myFile.xlsx", "false", null);
                XmlNode ndListItems =
                    listService.GetListItems("Test List", null, ndQuery,
                    ndViewFields, null, ndQueryOptions, null);
            }

            catch (System.Web.Services.Protocols.SoapException ex)
            {
                Console.WriteLine("Message:\n" + ex.Message + "\nDetail:\n" +
                    ex.Detail.InnerText +
                     "\nStackTrace:\n" + ex.StackTrace);
            }
        }
    }
}

The call to CheckOutFile() works correctly. But the GetListItems() call gives me this error:

An unhandled exception of type 'System.Net.WebException' occurred in System.Web.Services.dll

Additional information: The request failed with HTTP status 401: Unauthorized.

I don't understand why CheckOutFile() succeeds but GetListItems() fails, especially because the document that I'm checking out is in the list that's being accessed by GetListItems().

Answer 1

I resolved this by changing the web service's URL in app.config; see this StackOverflow answer.