19004: Invalid or missing Contact input

This error occurs when you send a contact request body with invalid or missing input. If you use Bulk Upsert Contacts, Twilio returns validation details for each correlation_id through error_code and error_messages so you can identify the contact record that failed.

• A required field is missing from the contact payload.
• The payload includes a duplicate field or an invalid field name.
• The request body is malformed or includes unsupported fields for the contact endpoint you called.
• If you are creating a contact, the payload may be missing a supported identifying field such as first_name, middle_name, last_name, legal_name, preferred_name, unique_customer_provided_id, or channel.

• Validate the request body against the Contact API schema before you retry the request. If you use Bulk Upsert Contacts, include the required items array.
• Add any missing required field, remove duplicate or unsupported fields, and correct invalid field names before resubmitting the request.
• If you use Bulk Upsert Contacts, review the error_code and error_messages values returned for each correlation_id to identify the exact contact record that failed validation.
• If you send a phone number in contact_id, format it in E.164.
• If you are creating a contact record, include at least one supported identifying field such as first_name, middle_name, last_name, legal_name, preferred_name, unique_customer_provided_id, or channel.

• Contact API
• Compliance Toolkit for Programmable Messaging
• Consent Management API