Not able to create a Styleable Hubspot form

Hi, I have just downloaded and successfully connected the Hubspot integration app available for Webflow.
Unfortunately when trying to add a styleable form to my page (first option, as you can see in the picture), the app hangs out in a neverending spinner

However, if what I add is a non-customizable embed (an iframe) it does work

Any idea about why this is happening or what I can do to solve it?