Modal form when button clicked not work

My Mautic version is: v3.3.3

My problem is:
Hey!
I am trying to call a modal when a button is clicked. I do it according to the manual Forms | Mautic
but there is clearly an error because

{mauticform id=2 style=modal element=.call-to-action-btn}

does not convert to form, but remains text.