Debian 7 设置，使用 Virtualmin/Webmin
最近，我收到一些人的投诉，他们报告说，从我托管在 VPS 上的一个网站收到了相同的电子邮件，多达 300 次
快速浏览日志会返回很多行，如下所示：
postfix/error[12555]: 50C35800D: to=<******@tiscali.it>, relay=none, delay=173374, delays=173374/0.03/0/0.01, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with etb-4.mail.tiscali.it[213.205.33.61] while sending end of data -- message may be sent more than once)
显然，此错误仅适用于拥有 @tiscali.it 电子邮件的人，但我不明白为什么，也不知道如何阻止它
我是否应该禁用延迟功能？从长远来看，这会导致其他问题吗？
更新 1
以下是来自 mail.log 的更详细的日志
postfix/smtp[5392]: smtp_get: EOF
postfix/smtp[5392]: connect to subsystem private/defer
postfix/smtp[5392]: send attr nrequest = 0
postfix/smtp[5392]: send attr flags = 0
postfix/smtp[5392]: send attr queue_id = 8780426101
postfix/smtp[5392]: send attr original_recipient = *@tiscali.it
postfix/smtp[5392]: send attr recipient = *@tiscali.it
postfix/smtp[5392]: send attr offset = 604
postfix/smtp[5392]: send attr dsn_orig_rcpt = rfc822;*@tiscali.it
postfix/smtp[5392]: send attr notify_flags = 0
postfix/smtp[5392]: send attr status = 4.4.2
postfix/smtp[5392]: send attr diag_type =
postfix/smtp[5392]: send attr diag_text =
postfix/smtp[5392]: send attr mta_type =
postfix/smtp[5392]: send attr mta_mname =
postfix/smtp[5392]: send attr action = delayed
postfix/smtp[5392]: send attr reason = lost connection with etb-2.mail.tiscali.it[213.205.33.64] while sending end of data -- message may be sent more than once
postfix/smtp[5392]: private/defer socket: wanted attribute: status
postfix/smtp[5392]: input attribute name: status
postfix/smtp[5392]: input attribute value: 0
postfix/smtp[5392]: private/defer socket: wanted attribute: (list terminator)
postfix/smtp[5392]: input attribute name: (end)
postfix/smtp[5392]: 8780426101: to=<*@tiscali.it>, relay=etb-2.mail.tiscali.it[213.205.33.64]:25, delay=129, delays=0.05/0.02/78/50, dsn=4.4.2, status=deferred (lost connection with etb-2.mail.tiscali.it[213.205.33.64] while sending end of data -- message may be sent more than once)