The error occurs because of a version mismatch between one of your dependencies and flutter_inappwebview. The issue specifically appears in iOS builds with the error.

@nicholas_randall is correct. Update your pubspec.yaml to use the correct version of flutter_inappwebview:

flutter_inappwebview: ^6.1.0+1

Then run:

flutter clean
flutter pub get
cd ios
pod install

Why This Works:

1. flutter_inappwebview 6.1.0 and later includes updated Swift method signatures that are compatible with the latest iOS WebKit changes
2. The clean and reinstall process ensures all native dependencies are properly aligned
3. Running pod install updates the iOS native dependencies to match the new version.

If you're still having issues after updating, you might need to:

1. Delete the Pods directory in your iOS folder
2. Delete the Podfile.lock file
3. Run pod deintegrate in the iOS directory
4. Then run the above commands again

This ensures a completely clean installation of the updated dependencies.