Marketpress permissions


I’ve tested the plugin on a localhost and everything works fine. When I upload files and database, I have all my products and everything seems ok… BUT when I test it… Paypal Express which was working on localhost doesn’t on the server… No message error, just it just does not go to the paypal page. Page stay blank.

API information are OK. Everything is exactly set as it is in localhost.

What should be permissions for :

folders : 755 ?

files : 644 ?

Is there a cache somewhere ?

Thanks for your reply.