Didn't have much luck with it myself
Scanned the code three times and it said there was a problem with Paypal. I check my Paypal account, which was fine and even held my Shell points card.
The fourth and fifth time, a different message came up which said there was a technical fault.
To top it all off, once I finally gave up on the idea and decided to pay inside, it took forever for the pump to start.
Goshdarnit.