XMLHttpRequest cannot load http://127.0.0.1:3000/ajax_send_email. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access.
버튼을 클릭하면 위에 에러를 보게 됩니다. 어떻게 처리하면될가여?