The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state.

A piece of code that I've been working on lately started to throw exceptions when calling a web service using a generated client. The log file contained only the exception message:

"The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state."

Most of the suggestions found in Web blamed the invalid code, giving examples similar to the following one:

using (MyWebServiceClient service = new MyWebServiceClient())
{
   service.DoSomeOperation();
   service.Close();
   service.DoAnotherOperation();
}

Since I was sure this was not the case I had to discover the real exception reason by myself.

Solution:

The using statement in the form presented above will mask any errors coming from the web service client and throw the "faulted state" exception instead, which may be irrelevant to the actual problem. To find out the real issue you can examine the InnerException property of the exception thrown (e.g. by logging it or debugging your app).

Alternatively you can add an additional try/catch to ensure that the real exception is thrown by your application rather than the "faulted state" one:

try 
{
   MyWebServiceClient service = new MyWebServiceClient()      
   service.DoSomeOperation();
   service.Close();
}
catch (CommunicationException e)
{
   service.Abort();
}
catch (TimeoutException e)
{
   service.Abort();
}
catch (Exception e)
{
   service.Abort();
   throw;
}

You can read more about the reason for the "faulted state" exception on MSDN page (Thanks to Carl for the link).