✅ .NET MAUI System.Reflection.TargetInvocationException

public SelectedOverviewViewModel()
        {
            CharactersList.Add(new CharacterModel
            {
                Name="Hi"
            });

            List<CharacterModel> characters = new List<CharacterModel>();
            characters = JsonConvert.DeserializeObject<List<CharacterModel>>(JSONstring); // Crashes here

            foreach (CharacterModel character in characters)
            {
                CharactersList.Add(character);
            }
        }

        [RelayCommand]
        void Load()
        {
            List<CharacterModel> characters = new List<CharacterModel>();
            characters = JsonConvert.DeserializeObject<List<CharacterModel>>(JSONstring);

            foreach (CharacterModel character in characters)
            {
                CharactersList.Add(character);
            }
        }