Pardot Form and Zoom Confirmation Email ISSUE

I want to pliot webinars using zoom but form is in pardot.

I followed step by step instructions here - https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0068276#creating-registration-forms

Issue:

1. My registrations are not syncing with zoom and i am not receiving confirmation email
2. if i use 

   <script> 
   document.forms[0].submit() 
   </script>

I am getting an internal server error -