iCloud: If you’re not receiving event and shared calendar notifications
If you’re not receiving notifications about events and shared calendars while signed in to iCloud.com or on your devices set up with iCloud Calendar, you may need to change your iCloud Calendar settings.
Change iCloud Calendar settings
In iCloud Calendar, click the Action pop-up menu
in the sidebar, then choose Preferences.In the Advanced pane, select “In-app notifications,” then click Save.
Last Modified: Sep 21, 2016