I'm following the [Walkthrough: Binding WPF Controls to a WCF Data Service](http://msdn.microsoft.com/en-us/library/dd465161%28v=vs.100%29.aspx)

But when I try to Discover the service I get an error saying that there was an error downloading metadata from the address

![enter image description here](https://i.stack.imgur.com/weqpq.jpg)

What could it be?

**EDIT**:

It basically creates an ASP NET Web App, adds an ADO Nen Entity Model, Adds a WCF Data Service, adds a WPF App to the solution, and tries to add a new data source from the service, the Add Service Reference appears, and it's there where the error appears.