Authentication with access token not working on flutter

Help
,
1

Hello, i dont know what i am doing wrong but for some reasons i can’t access my api i keep getting

{error: not_authenticated, description: The user does not have an active session or is not authenticated}

my flutter code:

Future fetchParentDetails() async {
    try {
      var url = Uri.parse(
        'https://mobile-api-teal.vercel.app/api/parent/get',
      );
      isLoading.value = true;
      final token = box.read('token');
      var response = await http.get(
        url,
        headers: {
          'Content-Type': 'application/json',
          'Authorization': 'Bearer $token',
        },
      );
      isLoading.value = false;
      if (response.statusCode == 200) {
        // handle successful response
        print(json.decode(response.body));
      } else {
        // handle error response
        print(json.decode(response.body));
      }
    } catch (e) {
      isLoading.value = false;
      rethrow;
    }
  }

Thanks