In some particular cases, it may not be possible to get immediate feedback about the actual execution of an instant transfer from the beneficiary's bank. For these transfers, the outcome of the payment is "verify".
In order to check if these transfers have actually been executed, it is sufficient to call the payment list API after ten minutes from the execution and check if the transfer in question is present in the list. If yes, it means that it has been correctly executed, otherwise the transfer has failed.