Dialog from service not showing on lollipop when screen is locked

问题

I am trying to show a Dialog from service in onStartCommand method

private Dialog incomingCallDialog;

incomingCallDialog = new Dialog(MyService.this, R.style.PopupDialog);
        incomingCallDialog.setCancelable(false);
        incomingCallDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        incomingCallDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
        incomingCallDialog.setContentView(view);

Handler delayHandler = new Handler();
        delayHandler.postDelayed(new Runnable() {
            @Override
            public void run() {                
                    incomingCallDialog.show();               
            }
        }, 100);

This code works fine in SamsungS5 which has Kitkat and when device is locked but it doesn't work on SamsungS6 which has lollipop 5.0.2 when device is locked.

The dialog is not showing at all in Lollipop when device is locked.