Fiddler4 cannot capture websocket requests from android app

I am trying to capture application requests using fiddler4. http requests can be captured smoothly by installing fiddler and andriod mobile. As you know, fiddler4 already supports websocket. I also found that Fiddler4 can capture websocket requests from the Chrome browser (I am using http://www.websocket.org/echo.html for testing).

But it cannot grab any websocket request from my application. I have printed all sessions in the log by adding "FiddlerApplication.Log.LogString (oSession.ToString ()); to OnBeforeRequest.

I am using: Fiddler Web Debugger (v4.5.1.2) my android app websockt java_websocket ( http://java-websocket.org/ )