用<CR><LF>.<CR><LF>结束数据，邮件未发送

Question

我知道，这个smtp状态已经有了答案，但是很抱歉:我不明白。我的一位客户发了大量邮件，有些邮件无法发送，原因是：

This is the mail system at host mailserver.blabla.local.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<mail@domain.de>: host mail.hostingserver.de[ip] said: 354 End data
    with <CR><LF>.<CR><LF> (in reply to end of DATA command)

更多信息：

Final-Recipient: acc1; mail@domain.de
Original-Recipient: acc1;info@domain.de
Action: failed
Status: 5.5.0
Remote-MTA: dns; mail.hostingserver.de
Diagnostic-Code: smtp; 354 End data with <CR><LF>.<CR><LF>

Return-Path: <sender@domain.de>
Received: from localhost (localhost [127.0.0.1])
    by neptun.migra-mv.local (Postfix) with ESMTP id 071A07418E6;
    Thu,  3 Nov 2016 12:04:22 +0100 (CET)
X-Virus-Scanned: by amavisd-new-2.10.1 (20141025) (Debian) at migra-mv.local
Received: from mailserver.blabla.local ([127.0.0.1])
    by localhost (mailserver.blabla.local [127.0.0.1]) (amavisd-new, port 10024)
    with ESMTP id ZkXsQejEkDHg; Thu,  3 Nov 2016 12:04:10 +0100 (CET)
Received: from [192.168.2.196] (unknown [192.168.2.1])
    by mailserver.blabla.local (Postfix) with ESMTPSA id 512A8741B70;
    Thu,  3 Nov 2016 12:03:31 +0100 (CET)
To: Migra MV <sender@domain.de>
From: IntegrationsFachDienst Migration MM <sender@domain.de>
Subject: =?UTF-8?Q?Aktuell:_=c3=9cber_200_Bildungsma=c3=9fnahmen_auch_f?=
 =?UTF-8?Q?=c3=bcr_Zugewanderte_in_ganz_M-V?=
Message-ID: <045abb9f-de00-bdc5-cede-01e338164930@migra-mv.local>
Date: Thu, 3 Nov 2016 12:03:51 +0100
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.2.0
MIME-Version: 1.0
Content-Type: multipart/mixed;
 boundary="------------55D5725BF82BAD7B1782022E"

为什么我们会收到这个错误并且没有发送消息呢？事实上，大多数消息都是毫无问题地发送的。这可能是收件人的错误吗？

Answer 1

可能和这个答案一样。客户端或服务器没有正确地遵循协议。