WorkManager not running periodically when app is closed on Android API28

Question

I want to run some tasks periodically while the app is closed. It works fine on Android API26 but on Android API28. I am using WorkManager 2.0.1.

MainActivity.java

PeriodicWorkRequest refreshWork;
refreshWork = new PeriodicWorkRequest.Builder(MyWorker.class, 16, TimeUnit.MINUTES)
.setConstraints(Constraints.NONE)
.addTag("MyTag")
.build();
 WorkManager.getInstance().enqueueUniquePeriodicWork("MyWorker", ExistingPeriodicWorkPolicy.KEEP ,refreshWork);  

MyWorker.java

public Result doWork() {
  Log.i("MyLog","I am here");
  return Worker.Result.success();
}