App Crashes On IOS Start Up In PCL Xamarin

PCL Project Which Crashes after Splash Screen on IOS
I have a try catch on IOS StartUp
On Main.cs

try
{
     UIApplication.Main(args, null, "AppDelegate");
}
catch (System.Exception exception)
{
     Crashes.TrackError(exception);
}

So i debug the project and it goes to App()
And When InitializeComponent();
It goes into catch with
Exception Message: Cannot invoke method with stack pointers via reflection

What causing this exception?
can someone help me out with it
P.S. : I tried updating Xamarin.forms version to some extend but had same issue
I can't update it to latest version because of dependency issues coz it's an old PCL project