551 <163.net.cn>, do
main not found. (RCPT TO:gldavid@163.net.cn) zh318@163.com,
553 Too many recipients in the mail, should less than 20 yongshiok@eyou.com,
553 Too many recipients in the mail, should less than 20 yhaochuan@21cn.com,
553 Too many recipien