Every SMS returns a delivery receipt (DLR) as it moves through the network. Common statuses:
- Delivered — the handset received it.
- Sent / Submitted — accepted by the operator, awaiting final confirmation.
- Failed / Undelivered — the operator could not deliver it (see the error code).
- Expired — not delivered within the validity window (often a phone off for too long).
See DLRs live in the dashboard, via webhooks, or in your downloadable CSV report.