Why do my SMS messages fail to send?

<h2 id="h_01HZ6P8ECD4TMZTGP5PXM8AFTP">Question</h2><div id="h_01HZ6P8ECD45ARQ38JVV693V42"><strong>Scenario A</strong></div><p>I receive one of the error messages below when I send an outbound Text message:</p><ul>
<li class="wysiwyg-list-bold" data-list-item-id="e642c0074a0359912cd7522f9d3775383"><strong>We couldn't deliver this message</strong></li>
<li class="wysiwyg-list-bold" data-list-item-id="e92c74fef3d87fb29e3fc71ff2e5979d3"><strong>We couldn't send the message</strong></li>
</ul><div id="h_01HZ6P8ECD3Q4ZHKBV527KACTW"><strong>Scenario B</strong></div><p>When I review the message details in my <a href="https://support.zendesk.com/hc/en-us/articles/4408846819226-Reviewing-Text-history#topic_b4l_f5q_xdb">Text history</a>, the status of my message is either <strong>Undelivered</strong> or <strong>Failed</strong>:</p><p><img src="https://support.zendesk.com/hc/article_attachments/11006972827418" alt="sms_undelivered_status"></p><p>Why are my SMS messages failing?</p><h2 id="h_01HZ6P8ECDG9RV6V2A0MEFZVC3">Answer</h2><p>Multiple reasons exist for SMS message failure. Common reasons why SMS messages fail to send:</p><ul>
<li data-list-item-id="e1242681b3f4e4a255dc2bdb3592d80a3">The destination handset is unreachable.</li>
<li data-list-item-id="e17809db252c0830d8fab0ad44258040b">The destination phone number doesn't support text.</li>
<li data-list-item-id="e2b6f1b41e8e419b0f24e224dffbb3611">The end user sent an opt-out code to one of my messages. For more information on opt-outs, see <a href="https://support.zendesk.com/hc/en-us/articles/4410645872154" target="_blank" rel="noopener noreferrer">About opt-out keywords for Zendesk Text</a>.</li>
<li data-list-item-id="e979d4fb039027f73aec0649647cb12b3">The destination number isn't local and international texting hasn't been enabled. Contact <a href="https://support.zendesk.com/hc/en-us/articles/4408843597850">Zendesk Customer Support</a> if you want to enable international texting.</li>
<li data-list-item-id="e10d6de544d542f506fb3ef95f815f49b">The destination number is located in a country where the text number doesn't support SMS long code international messaging. For example, Zendesk US text numbers can't send SMS messages to UK numbers. For more information, see <a href="https://www.twilio.com/en-us/guidelines/sms" target="_blank" rel="noopener noreferrer">Twilio's SMS guidelines</a>.</li>
</ul><p>If SMS messages still fail to send or if I need my US/CA toll-free numbers verified, Contact Zendesk Customer Support for further help. with the ticket ID where the SMS message failed.</p><style>
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<h2 id="h_01KXED8M7HWKCXPFXJJFGFB9VD">Why do my SMS messages fail to send? Why does my text message status say Undelivered or Failed? What causes Zendesk Text outbound messages to fail?</h2>
<p>SMS messages fail to send because the destination handset is unreachable, or the destination phone number does not support Text or text messaging. Outbound messages also fail if the end user or customer sends an opt-out code to one of your messages, or if the destination phone number is in a country where your Text number does not support SMS long code international messaging.</p>

<h2 id="h_01KXED8M7H5P11P1SWTFPBZMHH">Why do I see "We couldn't deliver this message" when sending text messages? Why do I get the error "We couldn't send the message" in Zendesk Text?</h2>
<p>You receive these errors due to several common issues. The destination handset is unreachable, the destination phone number does not support text messaging, or the end user or customer sent an opt-out keyword. Additionally, these errors happen when your Text number does not support SMS long code international messaging for the destination country, such as when US text numbers attempt to send SMS messages to UK numbers.</p>

<h2 id="h_01KXED8M7HZGKGSY9RNVSE611N">How do I fix failed or undelivered SMS messages in Zendesk? What should I do if my US or CA toll-free numbers need verification?</h2>
<p>If your SMS messages still fail to send or you need your US/CA toll-free numbers verified, contact Zendesk Customer Support or our team for further help. Ensure you provide the ticket ID where the SMS message failed when you reach out to support.</p>

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