Fixed the X.509 Certificate issue in WCF Test Client -The client certificate is not provided. Specify a client certificate in ClientCredentials

In our current project, we implemented X.509 Certificates. In order to test WCF methods, we needed to install X.509 certificates in our laptop. But when using SOAtest to run the tests or using WCF test client to invoke all methods, the following error message appeared:

The client certificate is not provided. Specify a client certificate in ClientCredentials.

How do we fix this issue in WCF Test Client? I assume you have the console app with the X.509 Cert configuration in app.config and the unit tests are working. 

Here are the steps to configure the WCF test client.

1. Open WCF Test Client.
2. Go to C:\Users\ray\AppData\Local\Temp\Test Client Projects\12.0.
3. Open Client.dll.config.
4. Copy all the contents of app.config into Client.dll.config and click save.
5. WCF test client will be refreshed and make sure you don’t see any error in Client.dll.config (Modify Contract name if required).
6. All WCF methods appear.

Input the parameters to invoke one WCF method and it is working without any certificate issue.