Not receiving any notifications from Instagram after updating to iOS 12? Well, it is not necessarily an iOS 12 issue but definitely an iOS problem because it has happened to a lot of users in the past.
You can check Instagram notifications setting for your iPhone by going to Settings » Notifications » Instagram and make sure Notifications are allowed for the app.
In case the Instagram app is missing under Notifications setting on your iPhone, then you need to delete the Instagram app and re-install to fix the Notifications problem.
- Hold the Instagram app icon from Home screen on your device until it jiggles.
- Tap the cross icon over the app icon.
- Tap Delete to remove the app from your iPhone.
- Open App Store, search for Instagram and download the app again.
Now go to Settings » Notifications » Instagram to make sure everything is normal again.