Provider Accepted Does Not Mean Delivered to the Inbox

Why it matters: Queued means work is waiting. Attempted means a worker tried to send. Provider accepted means the outbound service accepted responsibility for processing the message. Delivery events may arrive later, and a message can bounce after the initial API call succeeds. Show these distinctions when they are available rather than converting every successful request into a final success claim.

• Keep queue progress separate from delivery outcomes.
• Store provider message identifiers.
• Reconcile later events with the original recipient.

Why it matters: Open tracking can be affected by privacy features and image loading. Link activity can include automated security scanners. A reply is a stronger conversation signal but still needs interpretation. Use several metrics together and do not mark an address invalid simply because no open event appeared. Missing telemetry is not proof of failed delivery.

• Explain the limitations of open rates.
• Separate automated activity where possible.
• Prefer qualified replies over vanity metrics.

Why it matters: A temporary provider problem may justify a bounded retry. A confirmed invalid recipient usually requires suppression, not another attempt through a different sender. Preserve error categories so users can distinguish an authentication problem from a bad address. Accurate statuses make cancellation, retry and campaign reporting less confusing.

• Retry only eligible failure types.
• Do not resend successful recipients during a retry.
• Show unresolved outcomes honestly.