Todays cause of hair loss has been the following scenario:

I have a service that takes 2 strings and returns another. This service uses basicHttpBinding

<basicHttpBinding>
  <binding name="basicHttpNoSec">
    <security mode="None" />
  </binding>
</basicHttpBinding>

Anyway, it works fine from a console test app.

I have a silverlight app sat on top which implements another basicHttpBinding service that simply reuses the contract in the other service and the silverlight App uses this service.

I have a console app that confirms that this service is working and set up with basichttpbinding.

I have all the clientAccessPolicy stuff in place.

when I run the silverlight app the difference is that it runs everything async ... as such the only message i directly get back rom wcf is server not found.

When i enable tracing I dig down to this message - as I know the methods work and the parameteres i pass in will return a valid string i am really puzzled at to what the cause is. any help much appreciated.

<E2ETraceEvent xmlns="http://schemas.microsoft.com/2004/06/E2ETraceEvent">
 <System xmlns="http://schemas.microsoft.com/2004/06/windows/eventlog/system">
  <EventID>131075</EventID>
  <Type>3</Type>
  <SubType Name="Error">0</SubType>
  <Level>2</Level>
  <TimeCreated SystemTime="2010-06-07T14:17:40.6639249Z" />
  <Source Name="System.ServiceModel" />
  <Correlation ActivityID="{8ea9530e-12f4-4a82-9c26-dd2e23264c3c}" />
  <Execution ProcessName="aspnet_wp" ProcessID="4616" ThreadID="6" />
  <Channel />
  <Computer>5JC2Y2J</Computer>
</System>
<ApplicationData>
 <TraceData>
  <DataItem>
   <TraceRecord xmlns="http://schemas.microsoft.com/2004/10/E2ETraceEvent/TraceRecord" Severity="Error">
    <TraceIdentifier>http://msdn.microsoft.com/en-GB/library/System.ServiceModel.Diagnostics.ThrowingException.aspx</TraceIdentifier>
    <Description>Throwing an exception.</Description>
    <AppDomain>/LM/w3svc/1/ROOT/CopSilverlight.Web-1-129203938565564172</AppDomain>
    <Exception>
     <ExceptionType>System.ServiceModel.ProtocolException, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType>
     <Message>There is a problem with the XML that was received from the network. See inner exception for more details.</Message>
     <StackTrace>
at System.ServiceModel.Channels.HttpRequestContext.CreateMessage()
at System.ServiceModel.Channels.HttpChannelListener.HttpContextReceived(HttpRequestContext context, Action callback)
at System.ServiceModel.Activation.HostedHttpTransportManager.HttpContextReceived(HostedHttpRequestAsyncResult result)
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.HandleRequest()
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.BeginRequest()
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.OnBeginRequest(Object state)
at System.Runtime.IOThreadScheduler.ScheduledOverlapped.IOCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
at System.Runtime.Fx.IOCompletionThunk.UnhandledExceptionFrame(UInt32 error, UInt32 bytesRead, NativeOverlapped* nativeOverlapped)
at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)
     </StackTrace>
     <ExceptionString>System.ServiceModel.ProtocolException: There is a problem with the XML that was received from the network. See inner exception for more details. ---&gt; System.Xml.XmlException: The body of the message cannot be read because it is empty.
   --- End of inner exception stack trace ---</ExceptionString>
     <InnerException>
      <ExceptionType>System.Xml.XmlException, System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType>
      <Message>The body of the message cannot be read because it is empty.</Message>
      <StackTrace>
at System.ServiceModel.Channels.HttpRequestContext.CreateMessage()
at System.ServiceModel.Channels.HttpChannelListener.HttpContextReceived(HttpRequestContext context, Action callback)
at System.ServiceModel.Activation.HostedHttpTransportManager.HttpContextReceived(HostedHttpRequestAsyncResult result)
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.HandleRequest()
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.BeginRequest()
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.OnBeginRequest(Object state)
at System.Runtime.IOThreadScheduler.ScheduledOverlapped.IOCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
at System.Runtime.Fx.IOCompletionThunk.UnhandledExceptionFrame(UInt32 error, UInt32 bytesRead, NativeOverlapped* nativeOverlapped)
at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)
      </StackTrace>
      <ExceptionString>System.Xml.XmlException: The body of the message cannot be read because it is empty.</ExceptionString>
      </InnerException>
     </Exception>
    </TraceRecord>
   </DataItem>
  </TraceData>
 </ApplicationData>
</E2ETraceEvent>