flutter_secure_storage: Data of FlutterSecureStorage instance is null on iOS but not on Android

Hello, this code works on my Android app but not iOS. I tested it on a physical device and simulator.

class _MyHomePageState extends State<MyHomePage> {
  final storage = const FlutterSecureStorage();

  Future _containsKey() async {
    return storage.containsKey(key: "conciergeRowGuid");
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
        future: _containsKey(),
        builder: (context, snapshot) {
          return (snapshot.data == false)
              ? Scaffold(
                  backgroundColor: Colors.white,
                  body: Container(child: Text("not loaded"))
                )
              : FutureBuilder(
                  future: storage.read(key: "conciergeRowGuid"),
                  builder: (context, snapshot) {
                    if (snapshot.data == null) {
                      return SizedBox(
                        height: MediaQuery.of(context).size.height - 135,
                        width: MediaQuery.of(context).size.width,
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          crossAxisAlignment: CrossAxisAlignment.center,
                          children: const [
                            CircularProgressIndicator(
                              color: Color.fromARGB(255, 176, 64, 251),
                            ),
                          ],
                        ),
                      );
                    }
                    return Container(child: Text("loaded"));
                  });
        });
  }

In the iOS app, snapshot.data is always null. Digging into the iOS code of the Flutter Secure Storage, the functions of containsKey, write, read, readAll, deleteAll, all have groupId as nil. Also, OSStatus status has the error code 25300 which means errSecItemNotFound . And the return NSString *value is also nil. There is a similar issue #107 but the fix suggested is not working for me.

Specs: Flutter 2.10.4 flutter_secure_storage: ^5.0.2 MacOS Big Sur 11.6 Tested on:

• iPhone 13 Simulator iOS 15.0
• Physical iPhone 11 iOS 14.6
• Physical iPhone SE (2nd gen) iOS 15.4.1