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Error 63016 "Failed to send freeform message because you are outside the allowed window. Please use a Template." when Sending Programmable Messages to WhatsApp

If an outgoing message to WhatsApp returns a 63016 error code, this means an issue was found with the message you sent. This guide covers the following topics for diagnosing and resolving your issues:

Please start at the top, and walk through each of the troubleshooting steps as you work your way down the page.

Template vs Session messages

WhatsApp divides messages into two different types: Template messages and Session messages.

  • Template messages: Outbound messages sent via Twilio that use one of the pre-approved templates. These are generally unsolicited transactional messages (delivery alerts, appointment reminders, etc.) sent to users who have opted in to receive messages from you.
  • Session messages: All incoming messages, or outgoing replies to these messages within 24-hours. A messaging session starts when a user sends your application a message, and lasts for 24 hours from the most recently received message. Session messages do not need to follow a template, and can include media attachments.

Any messages sent to a destination that has not responded to you in at least 24-hours will need to be a Template message, and follow one of the pre-approved messaging patterns.

If you have confirmed that your response is outside of the 24-hour session window, continue to Review your message and templates. If you received this error within the 24-hour session window, please Escalate to Twilio Support

Review your message and templates

Approved WhatsApp templates can be seen by clicking an enabled phone number on the WhatsApp Senders page in Console.

Please verify the message you're attempting to send matches an approved template on the WhatsApp phone number. To compare your message and the approved template, you can use a service like Diffchecker (

  • Your message must follow the template as closely as possible, outside of any placeholders / values.
  • Your From address must match the WhatsApp enabled phone number.
  • WhatsApp does not permit using more than two consecutive (back-to-back) newline characters in a message, so ensure you are using no more than two newline characters consecutively within your message.
  • If the template you are attempting to use has a leading or trailing space or newline (\n) character, your messages will fail – please resubmit the template without leading or trailing space or newline characters.

If you have confirmed that your message matches the approved template, please Escalate to Twilio Support.

Escalate to Twilio Support

If you can rule out all of the above issues, Twilio's Support team can help investigate what went wrong with delivering your message(s). Please collect 3 or more examples of messages flagged with Error 63016 in your SMS logs from the last 24 hours, and include the following information:

  • SMS SIDs (If you have them)
  • Sending channel endpoint address (from)
  • Destination channel user address (to)
  • Your Twilio project Account SID
  • Timestamps of message attempts

When you have collected this information, please share it with our Support team.

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