Problem:

Some contacts using iPhones with iOS 15 and above do not see notification push alert banners or sounds from the Everbridge Mobile App. 

Root Cause:

Apple recently introduced changes to its push alert behavior in iOS 15 and above. These sometimes prevent apps from displaying push alert banners or sounds. 

Solution:

Changing one or more of the following features in iPhone settings usually solves the issue:

Focus Mode. If you have focus mode enabled, notifications might not show up on your iPhone. To check if focus mode is turned ON, open the Control Center and see if the mode is enabled. Turn it OFF to start allowing notifications again, or simply add the Everbridge app to the allowed apps under Allowed Notifications.
Scheduled Summary. Another new iOS 15 feature that can prevent notifications on iPhones is Scheduled Summary. To turn it off, open Settings > Notifications > Scheduled Summary and then disable it for all apps or just for the Everbridge Mobile App.
Announce Notifications. Some iPhone users have reported that enabling this feature allows notification push alerts to work again. To turn it on, in Settings > Notifications, tap Announce Notifications and turn it ON. Optionally, scroll down to the Everbridge Mobile App and enable Announce Notifications.