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SMS

Why a text failed and how to fix it

In Conversations, open the conversation, hover over the red warning on the text and note the error code. The code tells you the cause (contact opted out, invalid number, missing registration, filtered message…); fix it before resending.

Updated on

Before you start

  • You need access to Conversations and the contact's conversation.
  • Don't resend the same message over and over without fixing the cause: it hurts the number's reputation.
Where to find it

Conversations › contact's conversation › red warning on the text

Step by step

  1. Open Conversations and find the contact.
  2. Open the conversation and find the text marked Unsuccessful.
  3. Hover over (or click) the red warning next to the message and note the error code and description.
  4. Check whether the problem affects only this contact, only one sending number or all texts.
  5. Check the recipient: valid mobile number with country code (format +15551234567), not opted out and not on DND.
  6. Check the sending number: active, SMS-capable and, for the US, with an approved A2P registration.
  7. Check the message: attachments under 5 MB, valid links, no shorteners and no prohibited content.
  8. Fix the cause indicated by the code (see "Common problems").
  9. Send one test message. If it still fails, contact support with the sending number, the customer's number, the time and the error code (ideally 3 examples).

Tips

  • If the text came from a workflow, also check the workflow's execution log to find the error.
  • A failed text isn't automatically retried later.

Common problems

  • Error 21610 (contact opted out) → The customer replied STOP. Don't send more; they'll only receive texts again if they send START to the same number.
  • Errors 21211, 21614, 21635, 30005 or 30006 (invalid, landline or inactive number) → Fix the contact's number in international format (+ country code + number) or use another mobile number for them.
  • Error 21661 or 21606 (sending number not SMS-capable or unavailable) → Send from another SMS-capable number in the account or buy a number with SMS.
  • Error 30007 (message filtered by the carrier) → Review the text: identify your business, include opt-out language, remove link shorteners and pushy promotional content, and only text people who gave consent.
  • Errors 30032, 30033 or 30034 (US texts without registration) → The number isn't registered or linked to an approved A2P campaign. Complete A2P registration and link the number to the campaign; after approval, activation can take up to 24 hours.

Frequently asked questions

The text says "sent" but the customer didn't get it. What now?

Ask the customer to confirm their phone has signal and isn't blocking unknown senders. If it keeps happening with several customers, contact support with examples.

Why do texts to another country fail?

Sending to that country may not be enabled for the account (error 21408). Contact support to confirm whether the destination is available.

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