Here are ways to get notifications working.
Test
Somehow call the service-worker self.showNotification
Check OS-level permissions
Walk-throughs & screenshots, maybe for all combinations of OS &
browsers.
Mobile Phone - Apple iOS
Notifications require iOS 16.4 or higher. To check your iOS version,
go to Settings > General > About > Software Version.
Mobile Phone - Google Android
See the browser section.
Desktop - Mac
Requires Mac OS 13.
Check browser-level permissions
Walk-throughs & screenshots for browser settings
Mobile Phone - Apple iOS
Make sure your OS (above) supports it.
Mobile Phone - Android
Chrome requires version 50. Hold icon, select "App info", and enable
notifications.
Explain full reset to start again
Walk-throughs for clearing everything & subscribing anew to get a
message
Auto-detection
Show results of auto-detection whether they're turned on