Is there any workaround to allow the
works for external links, when I tried it it gave me
Webpage Can not be found
I can confirm this issue. The reason is the XSS protection. jQuery fancybox is a probably the best solution. For completeness I can tell about a solution I've seen:
So when you open a page in a modal dialog, you open your application page:
As I said, jQuery fancybox is much simpler and "fancier"...
It should work with any URL. If you can open the URL in the browser, you should be able to open it with