Hello Shanm2,
After reviewing your post, it sounds like there is trouble receiving notifications unless you open that specific app. Does this happen with any app other than Phone and Messages? It looks like you have already done some troubleshooting to solve this issue. Even though there is a chance that you've tried these steps already, I would recommend you follow every step and let us know if the issue persists.
"Most notification settings can be customized for each app. You can turn app notifications on or off, have notifications play a sound, choose how and where you want app notifications to appear when your device is unlocked, and more.
- Go to Settings  > Notifications.
- To choose when you want most notification previews to appear, tap Show Previews, then select an option—Always, When Unlocked, or Never. (You can override this setting for individual apps.)
- Previews can include things like text (from Messages and Mail) and invitation details (from Calendar).
- Tap Back, tap an app below Notification Style, then turn Allow Notifications on or off.
- If you turn on Allow Notifications, choose how and where you want the notifications to appear for the app—for example, on the Lock screen or in Notification Center.
- You can also set a notification banner style, sound, and badges for many apps.
- Tap Notification Grouping, then choose how you want the notifications grouped:
- By App:Â All the notifications from the app are grouped together.
- Automatic:Â The notifications from the app are grouped according to organizing criteria within the app, such as by topic or thread.
- Off:Â Turn off grouping.
To turn off notifications selectively for apps, go to Settings > Notifications > Siri Suggestions, then turn off any app."
Change notification settings on iPhone
Please don't hesitate to let us know if the steps resolved your issue or if you need additional assistance.
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