21657: The Sender ID is invalid

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.

• 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.

• 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.

• Configure your default Sender ID
• Alphanumeric Sender IDs in Messaging Services
• Messages resource