OverviewVM error handling

OverviewVM.cs

    private bool _isFaulted;
    public bool IsFaulted
    {
        get { return _isFaulted; }
        set { Set(ref _isFaulted, value); }
    }

    private string _errorMessage;
    public string ErrorMessage
    {
        get { return _errorMessage; }
        set { Set(ref _errorMessage, value); }
    }