---
page_type: error
code: 21714
message: "21714: Messaging Service Number Pool size limit reached"
level: ERROR
product: Programmable SMS
---

## Description

You have attempted to add a Twilio phone number, alpha sender, or short code to your Messaging Service Number Pool, but you are already at the limit of phone numbers or alpha senders. By default, a Messaging Service can contain up to a total of 400 Twilio phone numbers and short codes and only one Alpha Sender per country.

### Possible Causes

- Your Messaging Service number pool is already full (default: 400 numbers)
- You may have attempted to add more than one alpha sender for the same country to a Messaging Service or Sender Pool. Each country can only have one alpha sender assigned per Messaging Service Number Pool.

### Possible Solutions

- If you are sending to the United States and Canada, use a [Toll-Free or short code number](https://support.twilio.com/hc/en-us/articles/360038173654-Comparison-of-SMS-messaging-in-the-US-and-Canada-for-long-codes-short-codes-and-toll-free-phone-numbers) with higher message throughput (MPS), instead of adding more local numbers. Most mobile carriers in the US and Canada do not not permit [Application-to-Person (A2P)](https://support.twilio.com/hc/en-us/articles/223133807-What-is-P2P-and-A2P-messaging-) messaging via long codes, so there is a high risk of [carrier filtering](https://support.twilio.com/hc/en-us/articles/223181848-How-Does-Carrier-Filtering-Work-) when sending this type of traffic via long code.
- If you are sending to other countries, you may be eligible to have your Number Pool size limit increased. Please [submit a ticket](https://www.twilio.com/console/support/tickets/create) with a description of your use case and why you need a higher number pool size limit. These requests will be reviewed by our Messaging team.