---
page_type: error
code: 21655
message: "21655: The ContentSid is Invalid"
level: ERROR
product: Programmable SMS
---

## Description

The ContentSid you are using is not valid

### Possible Causes

The ContentSid you are using is not valid

### Possible Solutions

Double check the ContentSid parameter that you are using. Make sure it has the proper formatting and starts with an HX prefix.