What does this code mean, “404=Not Found; 404;-32601”? This occurs while joining a room in the Kurento media server

Question

I am working in android Application where i have stream a video. I am using kurento media server for Streaming . I am Connecting to KMS by using the following Code:

    executor = new LooperExecutor();
    executor.requestStart();

    String wsRoomUri = "wss://192.168.0.104:8433/kurento";
    kurentoRoomAPI = new KurentoRoomAPI(executor, wsRoomUri, this);

    CertificateFactory cf;
    try {
        cf = CertificateFactory.getInstance("X.509");
        InputStream caInput = new BufferedInputStream(getAssets().open("kurento_room_base64.cer"));
        Certificate ca = cf.generateCertificate(caInput);
        kurentoRoomAPI.addTrustedCertificate("ca", ca);
    } catch (CertificateException |IOException e) {
        e.printStackTrace();
    }

    kurentoRoomAPI.useSelfSignedCertificate(true);

    kurentoRoomAPI.connectWebSocket(); 

It gets connected. But When I try to join the room it shows the error and Error is:

.vtt.nubotest E/MainActivity: Code:-32601 
04-18 17:30:18.061 11699-11938/fi.vtt.nubotest E/MainActivity: Data:null

I am Receiving error in :

@Override
    public void onRoomError(RoomError error) {
    Toast.makeText(MainActivity.this,"OnError",Toast.LENGTH_SHORT).show();
    Log.e(TAG,"Code:"+ error.getCode());

    Log.e(TAG,"Data:"+ error.getData());
    if(error.getCode() == 104) {
        showFinishingError("Room error", "Username already taken");
    }
}

In Server Error Log I can see the following Error in json Format:

Response: >{"error":{"code":-32601,"message":"Method not                      
found."},"id":4,"jsonrpc":"2.0"}