Im getting Error On plugin Connectivity while running my code

I dont know why i got this error but my code is perfectly correct...

```c#
public WelcomePage()
{
InitializeComponent();
CrossConnectivity.Current.ConnectivityChanged += Current_ConnectivityChanged;
}

protected async override void OnAppearing()
{
base.OnAppearing();

if (!CrossConnectivity.Current.IsConnected)
{
await DisplayAlert("Error Title", "Error Msg", "OK");
}
else
{
await DisplayAlert("Connected","Success","ok");
}
}

public async void Current_ConnectivityChanged(object sender, Plugin.Connectivity.Abstractions.ConnectivityChangedEventArgs e)
{
if (!e.IsConnected)
{
await DisplayAlert("Error Title", "Error Msg", "OK");
}
else
{
await DisplayAlert("Connected", "Success","Ok");
}
}

```