Troubleshooting Failed Deliveries

Inspect the delivery attempt timeline first. Timeout usually means the destination did not respond in time. DNS and TLS failures indicate network or certificate issues. 401 and 403 responses usually mean missing or invalid receiver credentials. 404 can mean the route changed. 429 indicates throttling. 5xx responses indicate destination instability.

Use response status, error type, duration, and response sample to decide whether to retry, replay, disable a destination, or move work to dead-letter review.