Display External App using Podio's Supermenu iFrame

I am trying to display an external database app on a server as a calculation field on Podio (https://muniadvisory.com/public/index.php) using the iFrame feature. How can I show the separate web page on the link because nothing shows up with the following code: '[native html](https://muniadvisory.com/public/index.php#globiflowiframe:native)'