---
page_type: error
code: 21661
message: "21661: 'From' number is not SMS-capable"
level: ERROR
product: Programmable Messaging
---

## Description

Phone numbers must be SMS-capable. Visit the [phone numbers page](https://www.twilio.com/console/phone-numbers/incoming) of your account portal to view a list of phone numbers that you own and to determine whether they are SMS-capable.

### Possible Causes

The number you are using is not capable of sending messages.

### Possible Solutions

- Check that you are using a Twilio phone number with SMS capabilities. You can see your purchased phone numbers and their capabilities in the [Twilio console](https://www.twilio.com/console/phone-numbers/incoming).
- Purchase an SMS capable number from the [Twilio Console](https://console.twilio.com/us1/develop/phone-numbers/manage/search?isoCountry=US\&types%5B%5D=Local\&types%5B%5D=Tollfree\&capabilities%5B%5D=Sms\&searchTerm=\&searchFilter=left\&searchType=number).