Verify first in Settings -> notifications -> App settings, that all toggles are checked.
iodéOS uses microG services: an open-source & privacy-friendly re-implementation of the Google Play Services. The ‘Google Cloud Messaging’ (GCM) push notification service, used by many apps & allowing them to send notifications to you, is activated by default. If you don’t receive these types of notifications it probably means that GCM was accidently unactivated. To reactivate it:
- Go to Settings -> System -> microG -> Google device registration -> uncheck and check again ‘Register device’.
- Go to Cloud Messaging -> uncheck and check again ‘Receive push notifications’.
You should now be receiving notifications from your apps.