Thank u message after fill in a (caldera) form

On my third website, Ive granted access, I've made a form with caldera forms. On my website I have a button "reserveer" and if u click on it and fill in the form, usually after it youll see a "thank for filling in" message. Not anymore now, since a week. I didnt update any plugin. Could you have a look why the message don't showe up anymore?

At the moment the website is "under construction" but you can see my dashboard due the granted access.