---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/21607#article
headline: "21607: The 'from' phone number must be the sandbox phone number for trial accounts."
url: https://www.twilio.com/docs/api/errors/21607
inLanguage: en
dateModified: 2026-05-06T13:22:30.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 21607: The 'from' phone number must be the sandbox phone number for trial accounts.

Log Level: ERROR

## Description

While your account is in Trial mode, you can only send SMS messages from your free trial number, or the Twilio Sandbox Number.

### Possible causes

You attempted to send an SMS from a phone number other than your trial number or the Twilio Sandbox Number.

### Possible solutions

* Send SMS from your assigned trial number or the Twilio Sandbox Number.
* [Upgrade your account](/docs/usage/trials#upgrade-your-account) to remove this restriction.