Hi,
On page https://www.gnds.fr/preprod/sondage.html button "Terminer" is on activated.
Here's the message in Chrome Console :
Uncaught TypeError: form.ajaxSubmit is not a function
at Object.CjSurveyApi.submitAjaxForm (cj.surveys.min.js?v=1579067405:1718)
at HTMLButtonElement.onclick
Let me know if you need super user credentials.
Many thanks for your help.
Regards.