We upgraded to prestashop 1.6.0.11 (from 1.4.7)
The website worked perfectly including paypal, we received paypal payments and orders so its 100% fine.
A few days later, our hosting company (hostgator) said our CPU usage went over their limit and they put a restriction on our account for 24 hours, which meant the website would be cached and only updating sometimes (every 6 hours i believe)
While in cache mode our website was full of errors and bugs, the most important one being PAYPAL MODULE STOPPED WORKING.
After 3 days (they were busy according to them) they lifted the restrictions on our hosting. But the paypal problem remained.
PAYPAL PROBLEM: the customer can go through the checkout, choose paypal, go to the paypal screen, login, everything is fine EXCEPT when they finalize payment, they go to a blank screen with the url like thi
The payment actually goes through though, the payment lands in our paypal account. However in the backoffice there is no sign of the order what so ever.
We contacted paypal and they did a test as a test customer and the payment went through but again they landed on a blank screen with a url similar to the above and the order was NOT generated in the backend. Paypal said there is an issue with the paypal module but i guess thats where their customer service stops 
Can anybody please help us? Our business is almost non operational now because of this.
We are also having an issue with address (to be exact ''STATES'') not being sent to paypal. When the customer lands on the paypal payment page their state is missing. However we have had some transactions go through where the state was showing in paypal payment page correctly and we still had the same error so im not sure if thats the issue or not.
If anyone can help it would be HUGELY appreciated.
Many thanks.
j