> For the complete documentation index, see [llms.txt](https://help.activenow.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.activenow.io/en/communication/sms-not-delivered-to-participant.md).

# SMS Message Not Delivered to a Participant

A participant says they didn't receive an SMS? The most common cause is an incorrect phone number in the system. Before looking for other reasons, confirm with the participant that the phone number on their profile is correct.

## Check the message status

You can check the status of every sent SMS in the communication history. Go to the ***Communication*** tab → ***SMS communication history***. Each message shows a delivery status.

Here's what each status means:

* **Delivered** — the message reached the recipient.
* **Sent** — the message was sent, but the operator hasn't returned a delivery report yet. This status usually appears shortly after sending.
* **Accepted** — the message was accepted by the operator for delivery.
* **Not delivered** — the message did not reach the recipient. The most likely cause is an incorrect phone number — verify it with the participant and resend the message.
* **Expired** — the operator attempted to deliver the message, but the recipient's phone was switched off or out of range during all delivery attempts.


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