What is the best way to check internet connection ?

Hey try this

[DllImport("wininet.dll")]
private extern static bool InternetGetConnectedState(out int description, int reservedValue);

public static bool IsInternetAvailable() => InternetGetConnectedState(out int description, 0);

private void Form_Load(object sender, EventArgs e)
{
    if (IsInternetAvailable())
        MessageBox.Show("Internet Available");
    else
        MessageBox.Show("Internet Not Available");
}