1. Make sure that the Push Notifications is on under Settings

  2. The app with not send a notification if the app is open

  3. Your phone must be off Do not disturb

  4. Check under Settings, then Apps, then Olarm that Push notification is enabled

  5. Check under Settings, then Battery Optimization, then apps, locate Olarm app and remove from list

  6. Check that data/wifi can run in the background for this app

  7. If notification still doesn't come through then clear cache and data

  8. There is an open issue for newer android versions with aggressive battery optimization

Did this answer your question?