Hi there,
I using latest PayPal Payments Pro (Direct Payment), here the link https://apps.oscommerce.com/3w4ed&paypal-payments-pro-direct-payment
Since install this addons, i often receive double/duplicate orders and payment from order pay via PayPal Payments Pro.
I have check the debug email, most of double orders showing after the customer receive error code 15005, with error param value 51 or 0051. Any idea how to fix this issue?