If you open the preview of your WebIQ app and press F12 this will open the developer console.
If you then click on the "Network" tab, reload the page by pressing F5 and then enter the hostname you wish to show inside the iFrame in the input field you can see whether the website you wish to embed prevents it from being embedded:
If this is the case then you unfortunately cannot do anything on your side.
The only solution would be that the website you wish to embed changes (or removes) the header so that embedding is allowed.
This is not a limitation of WebIQ, but a web technology feature.