First of all, make sure you are getting events on your timeline. You should see dark blue lines indicating an event.

If you verified you are getting those events then there could be a couple of reasons to why you're not getting email alerts or push notification alerts on mobile.
1) Notifications for events are turned off
Select the camera that you are having issues with in the Timeline. Click the double dot to engage the menu. Select "Edit".

The box below should appear:

Click the "Notifications Settings".

Here you have several options to turn on notifications. There are several types:
Events: Analytics - this is the most common and covers all types of events. This could be any event coming from the camera. Custom or Scheduled are API specific events and most likely won't apply here.
Cloud AI - If you have the Cloud AI addon use this to notify only on specific labels such as Car or Person.
Health - Always recommend to keep your camera health alert turned on.
Schedule - You can assign custom schedules for your notifications. Look here if you are not getting notifications as expected.
LPR - Only for license plate recognition black list notifications
2) No Email is Setup to Receive Notifications
Click on your "Username" menu, then click on Settings. You can add your email and adjust your notifications there.