I’ve occasionally run across this error and it can be very frustrating to pinpoint what the actual problem is. Debugging in Visual Studio does not always give helpful information either. I’ve spent up to 6 hours on this error before only to find the error to be a simple 2 minute fix.
Steps to Reveal the WCF Service Error:
1) Alter your web.config file where your WCF service behavior is defined to include exception detail in faults. This will allow us to see the information we need when the WCF service fails. Visual Studio should give much more helpful exceptions when this is enabled.
2) If you are still having problems, download, install, and run Fiddler. Fiddler is an HTTP debugging proxy which logs all HTTP traffic between you and the sites you are viewing. Analyze the traffic/requests to see if anything is abnormal.
3) Run your application and attempt to connect/consume your broke WCF service function. You should be able to see the failed request in Fiddler. Once the request that failed is found, inspect the request to view the exception detail message.