WKWebView does not display web page even though it

Question

So we have this app for some customer who insisted on keeping cart and checkout hybrid rather than developing native pages. Now they have an intermediate web page (let's call it IWP) that is showed before order confirmation page. While doing checkout on Mobile Safari, this web page is displayed and then user is redirected to order confirmation page. But on WKWebView used in my app, IWP never shows in the WKWebView. It completes loading the IWP and after a second user is redirected to order confirmation page. I have tried debugging the web view load cycle and web view completes and calls every delegate method till didFinishNavigation. Still the page does not show up on the web view.

Any ideas, thoughts and suggestions what could be causing this problem?