When it triggers
This event fires when the recipient’s mail server permanently rejects the email. Common causes include invalid email addresses, full mailboxes, or domain-level blocks.Payload
Payload fields
Unique identifier of the email.
Sender email address.
Recipient email address.
Email subject line.
Tags associated with the email. Each tag has
name and value string fields. Returns an empty array if no tags were set.ISO 8601 timestamp of when the email was created.

