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.

Invalid payload errors usually mean the receiver accepted the request but rejected the body shape. Destination unavailable errors can mean the host is down, a deploy is in progress, or an upstream dependency is refusing traffic.

Use response status, error type, duration, headers, and response sample to decide whether to retry, replay, disable a destination, or move work to dead-letter review. If the receiver changed behavior, fix the destination first and then manually retry or replay from the dashboard.