# 21401: Invalid Phone Number

Log Type: APPLICATION

Log Level: ERROR

## Description

### 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/messaging/api#alpha-sender-id) when messaging [countries where this feature is supported](https://help.twilio.com/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