Coupon Apply Button not working

Hello I have a site where the Apply Button of the coupon is not working, I had previusly same problem and I correct the theme causing the issue, now still I have the same problem.

I deactivatd all the plugins and switced to twentytwenty theme but still the same problem.

I have latest wp an all updates.

in the console I can see this answer to admin-ajax.php

<meta name=”viewport” content=”width=device-width, initial-scale=1.0″>{“success”:true,”code”:”FRUNIVIDEO”,”discount”:”100″,”discountType”:”perc”,”discountStr”:”FREEUNIVERSALVIDEO: – 100%”}