# 21657: The Sender ID is invalid 

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when the `From` value in your SMS request uses a Sender ID that is not supported for the destination. Alphanumeric Sender IDs are only available in supported countries, and some destinations require registration before you can use them.

### Possible causes

* You used an Alphanumeric Sender ID in a destination country that does not support it.
* The destination country requires Sender ID registration, and the sender is not registered yet.
* The `From` value does not match a registered Sender ID for that country, and no default Sender ID is configured.

### Possible solutions

* Review the SMS guidelines for the destination country and use a Sender ID that is supported there.
* Register the Sender ID before sending to countries that require pre-registration.
* If you send messages through a Messaging Service, configure a default Sender ID for the country so Twilio can use a compliant sender automatically.

#### Additional resources

* [Configure your default Sender ID](/docs/phone-numbers/default-sender-id)
* [Alphanumeric Sender IDs in Messaging Services](/docs/messaging/services/alphanumeric-sender-ids-in-messaging-services)
* [Messages resource](/docs/messaging/api/message-resource)