When I come to pay for the items I get redirected to PayPal, I submit my sandbox account details and all seems well and good, then I return to my site and see the error 'Internal Error'. Once (and only once the payment went through). But this message is so vague I have no idea where to start looking to track down the actual error. Or why just once it went through.
The odd thing about the one that went through was I was redirected to the PayPal site that has the old styling, not the more modern looking site.
Has anyone else experienced this? Know where to start looking?