Webhook errors

HTTP	Scenario	Resolution
`400`	`url` is not HTTPS, or targets a private / loopback address	Use a publicly reachable HTTPS URL
`400`	Invalid or too many `developerEmail` addresses	Provide up to 5 valid email addresses
`400`	Event payload exceeds the 65 KB size limit	Reduce the size of the payload
`404`	Subscription or event not found	Verify the ID belongs to your company
`409`	Company has reached the 10-subscription limit	Delete an unused subscription before creating a new one
`409`	An in-flight delivery exists for this event (retry rejected)	Wait for all in-flight deliveries to settle, then retry