Impossible to order products at /command page Prestashop 1.7

[Indigoextra]

I'm using Prestashop V1.7.3.3 and the free module PayPal V4.4.1.

I've activated the Paypal module and linked it to the account, but when you order a product and add it to the cart, on the /command page, if you press 'Continue' nothing happens.  There's no error message or anything, it simply sits there doing nothing.

Does anyone have a solution to this problem?

It's the same as the one that appears in the French forum here:
https://www.prestashop.com/forums/topic/844387-bouton-commande-avec-obligation-de-paiement-sans-effet-non-fonctionnel/

 

[Indigoextra]

We solved this problem by installing the Verifone e-commerce module instead and even though we didn't enable any of the checkout options on this module, the PayPal module is now working.