How to Vibrate phone when the screen is off or locked via a background service?

I have a service that checks for updates on my website and I would like it to be able to cause a vibration when a update is found even if the screen is off or locked.

The vibration currently only works if the screen is not off / locked. All other functions does work even if the screen is off / locked.

Vibrator vibrator = (Vibrator) getSystemService(VIBRATOR_SERVICE);
   long[] pattern = new long[]{0, 400, 200, 400};
   if (Build.VERSION.SDK_INT >= 26) { // New API
     vibrator.vibrate(VibrationEffect.createWaveform(pattern,0));
   } else { // Old API
     vibrator.vibrate(pattern, 0);
}

How can I vibrate a phone even if its screen is off? I've tried to use a WakeLock but that doesn't seem to be the problem?

I have all the permissions set, as its working when the screen is on.

from How to Vibrate phone when the screen is off or locked via a background service?