21709: Alpha Sender ID is Invalid or Not Authorized for this Messaging Service

The Alpha Sender ID being added to a Messaging Service is invalid or Alpha Sender IDs have not been enabled for this Messaging Service.

• The Messaging Service is not enabled to support Alpha Sender IDs.
• The Alpha Sender ID being added to a Messaging Service is invalid. Alphanumeric Sender IDs may be up to 11 characters. They may not be only numbers. Refer to this page for acceptable characters.

• Follow these steps to verify your Messaging Service is enabled to support Alpha Sender IDs. If it is not, please reach out to Support.
• Verify the Alpha Sender ID you are trying to add to the Messaging Service is valid. View formatting requirements here.