4005: Recipient does not support this message type

The recipient cannot receive this message type. iMessage app messages require the recipient to be reachable over iMessage and do not fall back to SMS/RCS. This is an HTTP 422 error, delivered asynchronously as a message.failed webhook.

• Confirm the recipient is iMessage-capable before sending app messages — see the iMessage capability check
• Or send a standard text or media message, which can fall back to SMS/RCS

• iMessage Apps
• Webhook Events
• Error Codes