Thread Error on Button Click

<ComboBox SelectedItem="{Binding SelectorDomain.SelectorDTO.Name}"/>

<Button Content="+" Command="{Binding SelectorVM.AddEmulatorCommand}"/>

public ViewModel(){
var canAddEmulator = this.WhenAnyValue(vm => vm.SelectorDomain.SelectorDTO.Name).Select(name => name != "Select an Emulator");
AddEmulatorCommand = ReactiveCommand.Create(AddEmulator, canAddEmulator);
}

private async void AddEmulator()
        {
            try
            {
                String selectedEmulator = SelectorDomain.SelectorDTO.Name?.Trim();

                if (String.IsNullOrWhiteSpace(selectedEmulator))
                    return;

                String unformattedEmulator = NameFormatter.UnformatEmulatorName(selectedEmulator);
                await SelectorDomain.SelectorModel.SelectEmulatorAsync(unformattedEmulator);
            }
            catch (Exception ex)
            {
                Debug.WriteLine($"Exception in AddEmulator: {ex}");
            }
        }

        public async Task SelectEmulatorAsync(string emulatorName)
        {
          
                if (!String.IsNullOrWhiteSpace(emulatorName))
                {
                    emulatorName = emulatorName.Trim();
                    var emulator = await Context.Emulators
                        .Where(e => e.Name.Trim() == emulatorName)
                        .FirstOrDefaultAsync();

                    if (emulator != null)
                    {
                        await Context.SaveChangesAsync();
                    }
                }
            }
        }