Need some help making shortcode results become embeded content

I have a shortcode for a plugin I have been working on for my site.
I have tried to use the shortcode in an iframe to visit the url the shortcode produces.

The problem is, the shortcode seems to produce the url with no problems but the iframe skips it and produces a 404 redirect.

Can someone help me figure out a way to have my shortcode url to become an embeded page/iframe page on my site?

I have tried to add the shortcode directly as the src in an iframe - but this just dosen't work.

Help Please