
I'm using version 1.1.7 and when I performed the purchasing using paypal for the first time, it succeeded. But it was not the case for the next one. The second transaction failed with message "This invoice has already been paid. For more information, please contact the merchant." after I pressed the pay button (The message appeared in paypal's site). This happened also for the third one, forth one and so on even if I change my purchased products.
This problem occurs as if opencart sends the same id (or something) to paypal every time it initiate the transaction.
I would be very grateful if someone can help me with this problem.
Sorry for my bad english.
