---
page_type: error
code: 21607
message: >-
  21607: The 'from' phone number must be the sandbox phone number for trial
  accounts.
level: ERROR
---

## Error - 21607

### The 'From' number is not a valid, SMS-capable Twilio number

While your account is in Trial mode, you can only send SMS messages from your free trial number, or the Twilio Sandbox Number. To remove this restriction, [upgrade to a full account](/user/billing/upgrade).