If the server to which the webhook is notified cannot be notified due to network failure or other reasons, the response timeout (1.5 s) or error will be retried up to three times. If an error occurs even after the maximum number of retries, the webhook will not be sent. Therefore, full notification cannot be guaranteed: if the webhook is not delivered, the status of the transaction can also be checked via the Settlement Reference API.
In addition, if an error occurs during settlement (e.g. an error when multiple payments of the same amount are executed in a short period of time), the webhook will not be notified.
Note: Webhook notifications are not provided while PayPay is under maintenance.