When you are running/deploying Mule 3.8 applications you should note that TLSV1 is disabled by default as it has security vulnerabilities. So any application that you develop should be supporting only TLS1.1 and TLS1.2. If you have a https listener in your application and you want to send a request using the Fiddler, it may complain the following error:

org.mule.module.http.internal.listener.grizzly.MuleSslFilter: SSL handshake error: Client requested protocol TLSv1 not enabled or not supported

The fix for the error should be as follows:

1. Make sure that the Fiddler version is latest (>= .NET 4.0)
2. By default Fiddler supports only TLSV1 and so we need to add TLS1.1 and TLS1.2 so that Fiddler sends the request using the server supported TLS version i.e. in our case it is our mule runtime.
3. Go to “Tools” option in the menu item and click “Fiddler Options“.
4. Then select “HTTPS” folder.
5. If the checkbox “Decrypt HTTPS traffic” is not checked, then check it.
6. You should see “Protocols” with a hyperlink to click.
7. Click on the link and add this text or append to the existing text: “<client>;ssl3;tls1.0;tls1.1;tls1.2”.
8. Then CLOSE and RE-OPEN the Fiddler. You should be good sending requests to your Mule application now.

Here are the screenshots:

Hope this helps!