How can the problem of "Notifications are not allowed for this application" be resolved in flutter and firebase_messaging?

edit

There are a few potential solutions for this issue:

1. Make sure you have enabled notifications for the app in the device settings.

2. Check to ensure that the Firebase Cloud Messaging API Key and Sender ID are correctly entered in your app's firebase messaging service file, which can usually be found in the project's android/app directory, or the ios/Runner directory for iOS.

3. Check that your Firebase Cloud Messaging configuration is correct. This includes the correct package name and SHA1 fingerprint for your app, which can be found in the Firebase console under Project Settings > Cloud Messaging.

4. Ensure that you have added the necessary permissions for receiving push notifications in your AndroidManifest.xml and Info.plist files, depending on your target platform.

5. Verify that your app's Firebase Cloud Messaging token is being generated and updated correctly. You can do this by adding debug logs or breakpoints to your app's onTokenRefresh callback in the firebase messaging service file.

6. If none of these solutions work, try upgrading the Firebase Messaging version to a newer release to see if the issue has been resolved in a later version.