title: "Argument: NotFound" error using Windows Authentication for Silverlight
body: <p>A SL app created with SL Business Application template. Then Config it use Windows Authentication in web.Config as:</p>
  
  <pre><code>&lt;authentication mode="Windows"&gt;     
  &lt;/authentication&gt;
  </code></pre>
  
  <p>Code in App.xaml.cs to initialize authentication as:</p>
  
  <pre><code> webContext.Authentication = new WindowsAuthentication() 
       { DomainContext = new MyRIAServices.Web.AuthenticationContext() };
  </code></pre>
  
  <p>then move this app to IIS and set website under IIS as Widnows Authentication. 
  Then Run this app, it is fine, It can get domain account (AD acount logged into windows).</p>
  
  <p>Then move this app to anohter computer Windows 2008 R2 in the same domain. website under IIS configed exactly same as on windows 7. then access the sl app and got following error:</p>
  
  <pre><code>Load operation failed for query 'GetUser'.
  [HttpWebRequest_WebException_RemoteServer]
  Argument: NotFound
  Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem.
  See http://go.microsoft.com/fwlink/?linkid=106663&amp;version=4.0.50917&amp;File=System.Windows.dll&amp;key=httpWebRequest_WebException_RemoteServer
  </code></pre>
  
  <blockquote>
    <p>at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.End(IAsyncResult result)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.&lt;>c_<em>DisplayClass1.b</em>_0(Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.RunInSynchronizationContext(SendOrPostCallback callback, Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.HandleAsyncCompleted(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.AsyncResultBase.Complete()
       at System.ServiceModel.DomainServices.Client.ApplicationServices.WebAuthenticationService.HandleOperationComplete(OperationBase operation)
       at System.ServiceModel.DomainServices.Client.LoadOperation.&lt;>c_<em>DisplayClass4<code>1.&lt;Create&gt;b__0(LoadOperation</code>1 arg)
       at System.ServiceModel.DomainServices.Client.LoadOperation`1.InvokeCompleteAction()
       at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.LoadOperation.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.DomainContext.CompleteLoad(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.DomainContext.&lt;>c</em>_DisplayClass1b.b__17(Object )
    Caused by: Load operation failed for query 'GetUser'. [HttpWebRequest_WebException_RemoteServer]
    Arguments: NotFound
    Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See <a href="http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.0.50917.0&amp;File=System.Windows.dll&amp;Key=HttpWebRequest_WebException_RemoteServer" rel="nofollow">http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.0.50917.0&amp;File=System.Windows.dll&amp;Key=HttpWebRequest_WebException_RemoteServer</a></p>
    
    <p>at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.End(IAsyncResult result)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.&lt;>c_<em>DisplayClass1.b</em>_0(Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.RunInSynchronizationContext(SendOrPostCallback callback, Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.HandleAsyncCompleted(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.AsyncResultBase.Complete()
       at System.ServiceModel.DomainServices.Client.ApplicationServices.WebAuthenticationService.HandleOperationComplete(OperationBase operation)
       at System.ServiceModel.DomainServices.Client.LoadOperation.&lt;>c_<em>DisplayClass4<code>1.&lt;Create&gt;b__0(LoadOperation</code>1 arg)
       at System.ServiceModel.DomainServices.Client.LoadOperation`1.InvokeCompleteAction()
       at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.LoadOperation.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.DomainContext.CompleteLoad(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.DomainContext.&lt;>c</em>_DisplayClass1b.b__17(Object )
    Caused by: Load operation failed for query 'GetUser'. [HttpWebRequest_WebException_RemoteServer]
    Arguments: NotFound
    Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See <a href="http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.0.50917.0&amp;File=System.Windows.dll&amp;Key=HttpWebRequest_WebException_RemoteServer" rel="nofollow">http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.0.50917.0&amp;File=System.Windows.dll&amp;Key=HttpWebRequest_WebException_RemoteServer</a></p>
    
    <p>at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.End(IAsyncResult result)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.&lt;>c_<em>DisplayClass1.b</em>_0(Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.RunInSynchronizationContext(SendOrPostCallback callback, Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.HandleAsyncCompleted(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.AsyncResultBase.Complete()
       at System.ServiceModel.DomainServices.Client.ApplicationServices.WebAuthenticationService.HandleOperationComplete(OperationBase operation)
       at System.ServiceModel.DomainServices.Client.LoadOperation.&lt;>c_<em>DisplayClass4<code>1.&lt;Create&gt;b__0(LoadOperation</code>1 arg)
       at System.ServiceModel.DomainServices.Client.LoadOperation`1.InvokeCompleteAction()
       at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.LoadOperation.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.DomainContext.CompleteLoad(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.DomainContext.&lt;>c</em>_DisplayClass1b.b__17(Object )
    Caused by: Load operation failed for query 'GetUser'. [HttpWebRequest_WebException_RemoteServer]
    Arguments: NotFound
    Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See <a href="http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.0.50917.0&amp;File=System.Windows.dll&amp;Key=HttpWebRequest_WebException_RemoteServer" rel="nofollow">http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.0.50917.0&amp;File=System.Windows.dll&amp;Key=HttpWebRequest_WebException_RemoteServer</a></p>
    
    <p>at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.End(IAsyncResult result)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.&lt;>c_<em>DisplayClass1.b</em>_0(Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.RunInSynchronizationContext(SendOrPostCallback callback, Object state)
       at System.ServiceModel.DomainServices.Client.ApplicationServices.AuthenticationOperation.HandleAsyncCompleted(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.AsyncResultBase.Complete()
       at System.ServiceModel.DomainServices.Client.ApplicationServices.WebAuthenticationService.HandleOperationComplete(OperationBase operation)
       at System.ServiceModel.DomainServices.Client.LoadOperation.&lt;>c_<em>DisplayClass4<code>1.&lt;Create&gt;b__0(LoadOperation</code>1 arg)
       at System.ServiceModel.DomainServices.Client.LoadOperation`1.InvokeCompleteAction()
       at System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.LoadOperation.Complete(Exception error)
       at System.ServiceModel.DomainServices.Client.DomainContext.CompleteLoad(IAsyncResult asyncResult)
       at System.ServiceModel.DomainServices.Client.DomainContext.&lt;>c</em>_DisplayClass1b.b__17(Object )</p>
  </blockquote>
  
  <p>How to fix this problem?</p>