hang up after submit form

I use contact-form-7 withwpml for the translated pages for a total of two languages: de (1-language), fr (2nd-language)

For each language I have a contact form. This german language works well, if I press the submit button on the french translated page, the waiting sign will be displayed forever and the form will not be transmitted.

I have already tried to copy the text or the form from the German page or to apply the German form in the French page and still the same problem on the French side

Do you know the problem, do you have a solution approach?

The page I need help with: [log in to see the link]