What does an HTTP 404.3 error specifically indicate in the context of a WCF service?

An HTTP 404.3 'Not Found' error, when encountered with a WCF service, typically signifies that the client is attempting to access a service endpoint that doesn't exist or isn't properly configured within the WCF service definition. It's a less common error code than the standard 404, and often points to a misconfiguration rather than a genuinely missing resource.