---
page_type: error
code: 21710
message: "21710: Phone Number Already Exists in Messaging Service"
level: WARNING
product: Programmable SMS
---

## Description

The phone number, short code or alpha sender ID already exists in the Messaging Service.

### Possible Causes

- Multiple requests were made to add the phone number, short code or alpha sender ID to the Messaging Service's Sender Pool.
- The phone number, short code or alpha sender ID was already added at an earlier time.

### Possible Solutions

- If you know this phone number is properly associated with the Messaging Service, do nothing.
- Remove the existing phone number, short code or alpha sender ID from the Messaging Service and add it back to the Messaging Service's Sender Pool.