Modal or popup code not working

I am trying to get a form to be a popup on one of my wordpress buttons.  I can get it to embed just fine but anytime I try the modal or popup code it freezes wordpress.  

The button requires an http link, but how do I get that to function as a modal form? 

None of the embed codes seem to work.  Please help! 

Greetings and thank you for your message.

Have you tried to use Lightbox? This option will create a button for you, and all you need to do is to implement it on your website. You can also customize it from the form Publish tab:

If this solution does not work for you, please share with us the page URL so we can inspect the problem more deeply.

Thank you for your cooperation.