If you are following the Windows Azure (November CTP) SDK, and you are implementing the .NET Service Bus (AppFabric) Hands on lab called “Introduction to the .NET Service Bus”, then there is an error that you need to correct.

In task 4 titled “Task 4 – Creating the WCF Client Project “, the lab says that you create an interface IEchoContract and apply to it the following attribute:

[ServiceContract(Name = “EchoContract”, Namespace = “http://samples.microsoft.com/ServiceModel/Relay/”)]

Well the Name is wrong. if you have followed the lab manual precisely, then the Name should be “IEchoContract” instead.

If you run the sample without correcting the issue, you will be faced with the following exception:

The message with Action ‘http://samples.microsoft.com/ServiceModel/Relay/’ cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None).”

This problem can also appear if the namespace is different between the client and the service, so make sure to use the same namespace