silverlight - cross-domain problem -

I am using a silver with wcf and it runs when I use the .web project , But when using the light silver project, the following exception is thrown:

There was an error while trying to request the URI. This could be due to a cross-domain path without an appropriate cross-domain policy, or for SOAP services, trying to access a service without a useless policy. You may need to contact the service owner to publish a cross-domain policy file, and to ensure that the HTTP header related to SOAP allows the sending of the Web service proxy without using the InternalVisibleToAttribute attribute This error can also be caused by using internal type. Please see the internal exception for more information.

I want to use the silver light project to debug my code

thanks in advance

To access network resources from Silverlight, the hosting domain must provide the client access policy file; This is designed in such a way as for security reasons. See here for details: