UIWebView in Xamarin.iOS seems to ignore external

I'm facing a disturbing problem with showing HTML content in WebView, I've simplified the html content to this for easier reading:

<!DOCTYPE html>
<html lang="en">
    <head>
		<link href="https://www.paytabs.com/theme/payment_page/css/bootstrap.css" rel="stylesheet" type="text/css">
		<link href="https://www.paytabs.com/theme/payment_page/css/custom-rtl.css?timestamp=1540717040" rel="stylesheet" type="text/css">
	</head>

	<body>

<h1 class="text-primary">text one</h1>
<a href="www.stackoverflow.com" class="text-primary">StackOverflow</a>
<div class="container">
                
                    <div class="header-title"><h3>Xamarin</h3></div>
                
            </div>
	<h3 class="text-success">Success</h3>
	<img src="https://i.stack.imgur.com/PwBYM.jpg?s=328&g=1" alt="image"/>
	<h1 class="mark">Mark</h1>
	
	<div class="payment-wrap">
                    <div>
						<label class="payment_method">
                                <input type="radio" id="creditcard" name="payment_type" value="creditcard">
                                <img src="https://www.paytabs.com/images/img/cards.png" width="75" alt="Credit Card">
                        </label>
                                                                            
					</div>
                                           
                    <div class="form-wrap sadad-hide" style="display:none;">
                        <input class="form-control" placeholder="Enter user" value="" maxlength="12" name="olpalias" id="olpalias" autocomplete="off" type="text">
                    </div>
                    <span class="whats-this sadad-hide" style="display:none;">Don't have account?</span>
                    <!--Sadad Enable-->
                    <div id="pt-sadad-enable-outer">
                        <div id="pt-sadad-enable" class="pt-sadad-enable-wrap pt-arrow">
                        <div class="pt-sadad-enable-inner">
                            <h2>How to activate?</h2>
                            <ul class="pt-sadad-htp">
                                <li class="step1 step-help">
                                    <figure>
                                        <img class="img-help" src="https://www.paytabs.com/images/sadad/p1.png" width="50" height="32">
                                        <figcaption>Activate online</figcaption>
                                    </figure>
                                </li>
                                <li class="step2 step-help">
                                    <figure>				
                                        <img class="img-help" src="https://www.paytabs.com/images/sadad/p2.png" width="48" height="33">
                                        <figcaption>Create sadad account</figcaption>
                                    </figure>		
                                </li>
                                <li class="step3 step-help">
                                    <figure>								
                                        <img class="img-help" src="https://www.paytabs.com/images/sadad/p3.png" width="27" height="33">
                                        <figcaption>Add to your account</figcaption>
                                    </figure>						
                                </li>
                            </ul>
                        
                            <a href="https://www.sadad.com/ar/Personal/Pages/RegisterNow.aspx" class="pt-sadad-btn" target="_blank">learn more</a>
                        </div>
                    </div>
                    </div>
                <!-- End Sadad Enable Note-->

                </div>
	</body>

</html>

And here I set the Source of the webView:

 public MainPage()
        {
            InitializeComponent();
            webView.Source = new HtmlWebViewSource
            {
                Html = Resource1.testHtml //containing the HTML above
            };
        }

Here's what's shown on Android (normal):

iPhone:

I tried to use WkWebViewRenderer instead of UIWebView, by adding this in the AssembyInfo.cs file of the iOS project:

[assembly: ExportRenderer(typeof(WebView), typeof(Xamarin.Forms.Platform.iOS.WkWebViewRenderer))]

But this just shrunk the page size:

Any help?

cause: Since iOS 9, iOS will only allow your application to communicate with servers that implement best-practice security by default. Values must be set in Info.plist to enable communication with insecure servers.

Solution: Add the following code in your info.plist to trust your domain.

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSExceptionDomains</key>
    <dict>
      <key>www.paytabs.com</key>
      <dict>       
       <key>NSExceptionRequiresForwardSecrecy</key>
       <false/>
       <key>NSExceptionAllowsInsecureHTTPLoads</key>
       <true/>
       <key>NSIncludesSubdomains</key>
       <true/>
     </dict>
</dict>

For more detail you can access this document