21267: Alphanumeric Sender ID cannot be used as the 'From' number on trial accounts

This error occurs when you send an SMS from a trial account and use an Alphanumeric Sender ID as the From value. Alphanumeric Sender IDs are supported only on paid accounts.

• Your account is still in trial status.
• Your request uses an Alphanumeric Sender ID as the From value.
• Your messaging workflow is configured to send with an Alphanumeric Sender ID before the account has been upgraded.

• Upgrade your account before sending with an Alphanumeric Sender ID.
• Until you upgrade, send messages from an SMS-capable Twilio phone number in your account instead of an Alphanumeric Sender ID.
• After you upgrade, enable Alphanumeric Sender ID in your messaging settings and add the sender to your Messaging Service.
• If you continue with an Alphanumeric Sender ID after upgrading, confirm that the destination country supports it and complete preregistration when required.

• Get started with your Twilio free trial account
• Twilio Free Trial Limitations
• Alphanumeric Sender IDs in Messaging Services