Major Paypal Standard Problem

I noticed there was a similar problem in earlier versions of OC, but in the past week, paypal has suddenly decided to not update the OC store with created orders. I am using the latest version of OC and 10 days ago, it worked fine. Thankfully I can pick the order up in the paypal account but the customer has no order history nor do we have the order registering in the backend.

Any suggestions greatfully recieved!

Problem solved....settings in paypal admin were not changed to those shown in guidelines. Strange that it was working right up until last week though without tweaking these settings!