---
page_type: error
code: 21421
message: "21421: Phone Number is invalid"
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.