Check if below query returning result
INSERT INTO clients (code, sub_code, client_name, cat, email, [address],contact_phone, contact_phone2, active_phone, company_id_fk, procdure_id_fk, service_id_fk, procdure_date, user_id_fk,creation_date, transfer_date )
SELECT code, sub_code, client_name, cat, email,[address],contact_phone, contact_phone2, active_phone, company_id_fk,procdure_id_fk, service_id_fk, procdure_date, user_id_fk,creation_date, transfer_date
FROM archive_clients WHERE code NOT IN (SELECT code FROM clients )