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Troubleshooting SMS with Twilio Flex

Are you experiencing issues with sending or receiving SMS messages in Twilio Flex? If so, please check the following troubleshooting steps.

Not Receiving Incoming SMS in Flex

If you're not seeing incoming SMS in Flex, check if the incoming messages are arriving in your Twilio Project. Send another test message or two, and then check for new incoming messages using one of the following methods:

  • Look for any message failures in the Debugger page in Console.
  • Check the Programmable SMS Logs page in Console.
  • Check for Message Resources via the REST API.

If the messages are found in your Twilio project, but not hitting Flex, use the following Troubleshooting checklist:

  • Run a Flex System Checkup from Console, and cleanup any Inactive Chats.
  • Check the Studio Messaging Flow for any Stuck Executions.
  • Verify your phone number is correctly configured for Flex:
    • Access the Flex Messaging page in Console, and verify your Twilio phone number is listed under "Manage Flex Flows".
    • Access the Proxy Dashboard page in Console, and verify Flex Proxy Service lists your Twilio number under "Phone Numbers".
  • Revert the Studio Messaging Flow to the first revision.
  • Review the guide How do I troubleshoot my messaging setup (Twilio Docs).

If no messages are found in your Twilio project, please see Not Receiving Incoming SMS and MMS Messages on Twilio Phone Number.

Not Receiving Outbound SMS from Flex

If your outbound messages from Flex are not arriving to your wireless device, please check the following:

  • Navigate to the Programmable Chat Console.
  • Open the Flex Chat Service and navigate to Webhooks.
  • Verify the Post-Event Webhook is configured correctly:
    • The URL is pointing to the Flex Proxy Service.
    • The "onMessageSent", "onChannelUpdated" and "onChannelDestroyed" events are selected

If the messages still aren't being delivered, please see Troubleshooting Undelivered Twilio SMS Messages.

Still Having Trouble?

If you can rule out all the above issues, Twilio's Support team can help investigate what went wrong with delivering your message. Please open a support request with the following 3 or more Message SIDs (SMxxxx) from SMS logs that occurred with the last 24 hours and that show these same issues.


Have more questions? Submit a request
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