I am facing the same problem, i.e. During checkout, the user is sent to Paypal, payment is processed but the new order is not registered by Prestashop. The cart is not emptied either, however, the Paypal transaction completed successfully.
The order is not shown either on the admin site, though the transaction on the paypal sandbox shows as successfull. I am in UAE and using the Paypal USA module. Please advise, I was not expecting this basic behavior to be flawed or confiusing, or is there anything we all are missing here???
Prestashop version: 1.6.0.9
Paypal USA v 1.3.8
Regards,
Imran