The most common decline reasons for payments by card are:
In cases 1-3 customer usually can solve the issue promptly enough contacting bank support to: clarify correct expiry date, CVV2, recharge card, increase limit. Therefore, to allow the customer to retry without re-creating the order parameter
delayed is added in the protocol .
Using delayed payment allows to increase the proportion of successfully paid orders by conversion of rejected and not complete payments into successful ones.
Delayed order is different from the usual because customer may try to pay it many times, until order
lifetime expires. In this case merchant will receive response to
server_callback_url as many times as he tries to pay.
Indication that the order has not been completed, will be returned parameter
declined in case of delayed order will never be returned.