System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper Error Version 3.9

I creating my own payment method, when OpcCheckoutPage call PaymentInfo View i had an error.

Any idea ?

i try to added
web.config file, app.config file, packages.config and "@using Nop.Web.Framework" in View
but still giving error

Please give more details on the error

Here PaymentInfoViewModel Class

        public string IFrameSrc { get; set; }

        public bool IsVisible { get; set; }

        public bool IsFailed { get; set; }


Here PaymentInfo Method

        [ChildActionOnly]
        public ActionResult PaymentInfo()
        {
            /* other codes. */

            var model = PaymentInfoViewModel();
            model.IFrameSrc = "https://website.com/token"
            model.IsVisible = True;
            model.IsFailed = False;
            return View("~/Plugins/Payments.PayTR/Views/PaymentInfo.cshtml",model);
        }


Here View

@if (!Model.IsFailed)
{
        <script src="https://www.website.com/js/iframeResizer.min.js"></script>
        <iframe src="@Model.IFrameSrc"  id="paymentframe" frameborder="0" scrolling="no" style="width: 100%;">
        </iframe>
        <script>iFrameResize({}, '#paymentframe');</script>
}
else
{
    <label> Payment method couldnt load.. </label>
}