Doesn’t work with Themify?

FYI, to prevent the Themify Contact form from doing a normal (unencrypted) form submission, it is necessary to add some Javascript to the page to disable the normal form operation:

<script>
(function() { // Contact-us script

  function onready() {    // Adjust Themify forms for operation with XQ
      //console.log( 'Contact: onready' )
      const forms = jQuery( 'form.builder-contact' )
      if( forms && forms.length>0 ) {
          forms.addClass( 'sending hidden' )    // Hide spinner & prevent normal Themify form submission (let XQ script handle it)
          .on( 'submit', () => forms.removeClass('hidden') )   // Reveal spinner when Submit button is clicked
          console.log( forms.length + ' .builder-contact forms disabled ?' )
      }
      else console.warn( 'No .builder-contact forms found! ?' )
  }

  //console.log( 'Contact: run' )
  const tid = setInterval( () => {
      if( jQuery ) {    // Wait until jQuery is loaded
          //console.log( 'Contact: JQ loaded' )
          clearInterval( tid )
          jQuery( document ).ready( onready )
      }
  }, 200 )
})()
</script>

<style>
.builder-contact.sending.hidden .tf_loader {
    display: none;
}
</style>