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Troubleshoot SMS delivery

A text message you sent as part of a Broadcast did not send, or a subscriber says it never arrived. Use this page to narrow down the cause and confirm whether the failure is on your side, the carrier's, or the subscriber's.

Symptom​

  • An SMS Broadcast completed, but one or more subscribers report no message.
  • A subscriber's number shows as skipped, failed, or undelivered in your send report.
  • Messages to some subscribers deliver while others in the same Broadcast do not.

Likely causes​

Ranked from most to least common:

  1. The subscriber opted out. A prior STOP (or equivalent keyword) reply suppresses all future texts to that number. This is enforced automatically and cannot be overridden.
  2. Quiet hours blocked the send. Messages scheduled or triggered outside the allowed sending window for the subscriber's time zone are held or dropped to stay compliant.
  3. Invalid or non-mobile number. Malformed numbers, landlines, or VoIP numbers that cannot receive SMS will fail at the carrier.
  4. Missing or wrong country/region formatting. Numbers without correct international (E.164) formatting may be rejected.
  5. Carrier filtering. Carriers can silently block messages that look like spam (shortened links, all caps, high volume).

Fixes​

  1. Check opt-out status. Look up the subscriber and confirm they have not opted out. If they have and want back in, they must text the opt-in keyword themselves — you cannot re-subscribe them manually. (confirm the exact steps in your account)
  2. Review quiet-hours settings. Verify the send window and that subscriber time zones are set. Reschedule the Broadcast inside the permitted hours.
  3. Validate the number. Confirm it is a mobile number in correct E.164 format (country code included, no spaces or symbols). Correct or remove bad numbers in your audience.
  4. Simplify the message. Remove risky content (excessive links, all caps) to reduce carrier filtering, then resend to affected subscribers.
  5. Read the send report. Match each failure to its status reason to confirm the cause before resending.

Still stuck?​

If numbers are valid, not opted out, and sent within quiet hours but still fail, capture the Broadcast name, send time, and a sample failing number, then contact your account support team so they can trace the carrier response.

Canonical terms: Author, Edition, Folder (Project Folder), Broadcast. See the Glossary.