The Digital River Extension for Magento invokes an exception for all returned 400 and 500 response statuses. If you set Enable debug logging to Yes, all exceptions are logged.
400 invalid-request–The DrPay extension will ensure a proper payload.
409 resource-already-exists–For a guest checkout, the DrPay extension will create a new Digital River shopper each time to avoid a conﬂict. All users created will be created first in Magento and then in Digital River. If DrPay creates a user in Magento without creating a user in Digital River, an error occurs when the shopper attempts to use a stored credit card the second time through the order ﬂow. If DrPay did not use a saved cart, then Digital River will try to create the user during their next purchase.
500 Unable-to-place-order–The shopper will not be able to check out and will encounter a fatal error when attempting to place their order. They will see the following error message:
Unable to Place Order.
400 Unable to Place Order–All payment authorization failures will display this message.
409 invalid_token–If the token is invalid for any reason during the checkout, an error will occur while trying to place their order.
500 Unable to Place Order–Service unavailable will result in an error message.