webhook
failedNotification
Sent when a message you sent failed to be delivered by the channel.
eventType is NOTIFICATION and notificationType is FAILED.
The callback carries the FAILED status and the correlating outboundId
so you can identify which message could not be delivered.
Callback acknowledged.
Permanent failure. Enrich will not retry.
Transient failure. Enrich retries up to 4 times, 5s apart.