关于自动发邮件功能的问题

错误如下：uchome/data/log/201004_STMP.php

<?PHP exit;?>        2010-04-28 13:07:48                119.126.128.250        2        /do.php?ac=sendmail&rand=1272431266        (stmp.qq.com:25) CONNECT - Unable to connect to the SMTP server
<?PHP exit;?>        2010-04-28 13:17:26                119.126.128.250        2        /do.php?ac=sendmail&rand=1272431844        (stmp.qq.com:25) CONNECT - Unable to connect to the SMTP server
<?PHP exit;?>        2010-04-28 13:27:44                119.126.128.250        2        /do.php?ac=sendmail&rand=1272432463        (stmp.21cn.com:25) CONNECT - Unable to connect to the SMTP server
<?PHP exit;?>        2010-04-28 13:37:17                119.126.128.250        2        /do.php?ac=sendmail&rand=1272433036        (stmp.21cn.com:25) CONNECT - Unable to connect to the SMTP server
<?PHP exit;?>        2010-04-28 14:00:39                119.126.128.250        2        /do.php?ac=sendmail&rand=1272434438        (stmp.21cn.com:25) CONNECT - Unable to connect to the SMTP server
<?PHP exit;?>        2010-04-28 14:24:08                119.126.128.250        2        /do.php?ac=sendmail&rand=1272435847        (stmp.21cn.com:25) CONNECT - Unable to connect to the SMTP server
<?PHP exit;?>        2010-04-28 14:25:44                119.126.128.250        2        /do.php?ac=sendmail&rand=1272435943        (stmp.21cn.com:25) CONNECT - Unable to connect to the SMTP server

设置情况：


以上设置和DZ里面一致，但DZ的邮件发生正常，而UCH则发送不正常。