Putting a form in a modal popup

Developing with Concrete
1

A client has asked me to put a core form into a modal popup. I thought that seems like a simple request so i made a stack and put the form in that then call the stack in to a modal in my php.

But it fails to submit

Anyone else tried this with any success?

2

Are there JavaScript errors in the console?

3

It show a 404 on submit.