19013: At least one of the following fields is required for a contact: first_name, middle_name, last_name, legal_name, preferred_name, unique_customer_provided_id or channel
ERROR
Contact should contain at least one required field
Contact does not possess even one required field
Contact should contain at least one of the following fields - first_name, middle_name, last_name, legal_name, preferred_name, unique_customer_provided_id or channel