Please make sure to rename the app bundle package name to an individual, new, non-used app bundle package.
You might have to rename the front part of the Bundle Identifier on the Settings tab. Only renaming the front part will resolve the error.
While renaming your app bundle package name, it’s essential to follow the steps in the “Rename package name/build & publish your app” section of the documentation (video: https://www.youtube.com/watch?v=qZd98DEm9yI: Summary: You need to change the OneSignalNotificationServiceExtension Bundle Identifier to be {your app’s bundle ID}.OneSignalNotificationServiceExtension.
If actual app’s Bundle ID is com.example.ios.app, the bundle ID com.example.ios.app.OneSignalNotificationServiceExtension would be correct.
Moreover, please make sure to activate both the capabilities “App Groups” and “Push Notifications” in the App Identifier section on the Apple Developer Portal (choose the correct App ID here: https://developer.apple.com/account/resources/identifiers/list). See these screenshots: https://prnt.sc/xz4hg5 & https://prnt.sc/xz4j01 Restart Xcode afterward.
More ideas to fix this problem: https://stackoverflow.com/questions/44160993/xcode-error-the-app-id-cannot-be-registered-to-your-development-team
