Errors that appear in the WCF client app...

I was setting a new server to host my WCF app and I hit the wall with the following error messages. I spent 2 days in solving this problem. I guess, many people is wondering how to resolve these interesting errors.

• The server has rejected the client credentials.
• The socket connection was aborted. This could be caused by an error processing your message or a receive timeout being exceeded by the remote host, or an underlying network resource issue. Local socket timeout was '00:00:59.9687500'.
• The communication object, System.ServiceModel.ServiceHost, cannot be used for communication because it is in the Faulted state.

I have developed a WCF solution in WinForm which allows you to comment out certain settings in the server and client so that you can reproduce the above mentioned error message.

  https://github.com/lauhw/WcfWinForm

Please beware that if you are running the WCF server and client in the same computer, the above error might not appear until you run them in a separate computer.

In a nutshell:

1. Both server and client config file must have the same settings in the "Binding" record. This includes the "security mode".
2. The "identity" settings must be the same in both server and client config file.
3. In the live environment, make sure you remove the "MEX" endpoint unless you want anyone to be able to query the interface.
4. Don't forget to open the port in the firewall.

In case you are hitting the same error mentioned above, the fastest way to solve this problem is to run the test WCF solution (as mentioned above). Make sure that the test solution works. After that, compare the differences in app.config between the test solution and your solution.

Hope you don't have to spend 2 days to solve the configuration problem. ;)