Membership’s ‘Renew’ and ‘Complete Payment’ button are not working on my site

If I click on the ‘Renew’ or 'Complete Payment' button on this page https://***.org/membership-options/ the page reloads back to itself and nothing happens.
If I’m logged in with a current user I can’t renew my membership; the only step I can do is to 'Signup' to any of the other options, but after that, if I click on the 'Complete Payment' button the page reloads back to itself and nothing happens. So the same issue (page loading back to itself not changing anything) is happening for the 'Renew' and the 'Complete payment' buttons.