Iframe registerButtonDoneUrl redirect not working

I'm trying to figure out the proper steps when embedding the Trial Registration iframe on my site.  I've added everything I need to add and included sandbox and in the QLM I added the correct registerButtonDoneUrl address.  I'm still having issues with it not wanting to redirect to the correct page of my site.  The iframe just disappears after I click done.  The form works and I'm sent an email with key but i'm stuck on a blank page with nowhere to go.  Adding some sandbox attributes I now have a CORS issue.  I ended up adding all sandbox attributes to see if at least one of them would work.

See my code below with edits to my site name:

 <iframe

  style="border: 0px #ffffff none;"

  src=https://qlm3.net/mysite/QlmCustomerSite/qlmregistrationform.aspx?is_args=demo_order

sandbox="allow-top-navigation allow-top-navigation-by-user-activation allow-forms allow-scripts allow-popups allow-top-navigation-to-custom-protocols allow-same-origin allow-presentation allow-popups-to-escape-sandbox allow-modals"

          &is_emailfrom=%Email%

        &is_emailsubject="Your Download of tools"               &is_confirmationmessage="Your License information was emailed to:" %Email%

name="myiFrame"

width="100%"

height="580px"

frameborder="1"

marginwidth="0px"

marginheight="0px"

scrolling="no"

allowfullscreen="allowfullscreen">

</iframe>