---
page_type: error
code: 21401
message: "21401: Invalid Phone Number"
level: ERROR
---

## Description

## Error - 21401

### Invalid Phone Number

The phone number you specified was not a valid SMS-enabled phone number or alphanumeric sender ID.

If a phone number was used, this number must be one you have purchased from or ported to Twilio in [E.164 format](http://en.wikipedia.org/wiki/E.164).

Alphanumeric sender IDs can only be used with [accepted characters](/docs/api/rest/sending-messages#alpha-sender-id) when messaging [countries where this feature is supported](https://support.twilio.com/hc/en-us/articles/223133767-International-support-for-Alphanumeric-Sender-ID).

### Possible Causes

The phone number is not supported in North America.

### Possible Solutions

Try using a different phone number: https://www.twilio.com/phone-numbers