# 21421: Phone Number is invalid

Log Type: APPLICATION

Log Level: ERROR

## Description

You tried to purchase or lookup a phone number that is invalid or add a phone number to a Messaging Service with an invalid Phone Number SID.

### Possible causes

* You tried to purchase or lookup a phone number that is invalid.
* You tried to add an invalid Phone Number SID or Short Code SID to a Messaging Service.

### Possible solutions

* For phone number lookup or purchase, please specify a valid phone number in E.164 format.
* For adding a Phone Number to a Messaging Service, verify that the Phone Number SID or Short Code SID is correct and formatted properly, then retry the request.