我遇到了以下问题：我运行 Debian 服务器已有大约一年了，但始终无法正确发送邮件。它们不断被 Google 垃圾邮件过滤器拦截，Outlook 似乎根本不会发送邮件（甚至不会发送到垃圾邮件文件夹，日志显示“250：排队等待发送的邮件”）。现在我真的很绝望，我已经尝试了所有方法。SPF、DKIM 和 DMARC 已设置并正常工作，rDNS、TLS 加密等也是如此。我真的不知道我做错了什么。我发送的测试邮件的内容各不相同，从“测试邮件，请忽略”（最有可能被标记为垃圾邮件）到文章摘录或其他内容（成功发送的邮件，从我的 gmail 帐户发送）。像 mail-tester.com 或 mxtoolbox 这样的邮件信誉测试器会给我 100% 的分数，并且没有任何黑名单条目。这是来自 gmail 标记为垃圾邮件的电子邮件的示例标题：
Delivered-To: [email protected]
Received: by 10.13.219.204 with SMTP id d195csp864184ywe;
Thu, 25 May 2017 12:21:05 -0700 (PDT)
X-Received: by 10.223.168.120 with SMTP id l111mr23297935wrc.137.1495740065010;
Thu, 25 May 2017 12:21:05 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1495740064; cv=none;
d=google.com; s=arc-20160816;
b=qfY69gpmb0GQn3ZGvSEJyIxi+zr2DbvUyY993tWQep9z+ZN0vEIzWjXyofJCBkSWH2
sNutCeHIiMvfaloacvcMdWC5zoE/Pbf0TpEdNP+dnd+wXI112LXpVE+A8zA9MHoO0oEY
CC7hfCzDRNP0IF6b//1euhzlJvrhuj99wWDBTcvKd1x/CWQJW1qNq1sMERmzYiQ1wHDM
rnHbvkG385LihogIsdXhSZ4A93HCogl5ERUtr3+PT717pilkNUXZS4Hp6l8XFKXCOOnS
/1oFR0xBY5FeZcJ6Vt/+C2H/qB7NtYNc0G3IVkTa6nmaxtihQqZHZ+e8NfVJX7BBWxn1
nl/Q==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
h=content-language:content-transfer-encoding:mime-version:user-agent
:date:message-id:subject:from:to:dkim-signature:dkim-signature
:arc-authentication-results;
bh=acCgJp9ry6elq8fVTxHxfBFnaouI4MAk66UPTSH2BW4=;
b=Of8iF8mxuMrJZNYdVS+ni786ZuZNV7rnyLmz/bbu8O1StdBos4vAG8v2LaC3OFBvua
OxD0EHbxbsMoIveVMF9pHXHI4bN5YD53t+x7hv9SYqCdCmyG1HCcMFFt6otL5PvSPVwK
Q+beOiUjrp3TJ7btoSAWaPCdKSR41J39zTGrpowU/NYISQaUc5mt8Q4e2MHF/l6n9NRd
bNvtXIqPUVAOvzDeV2YpNAOquFa33gSsXB3PvcsE6z1UkjPR7TSj0/W5E6uUMPV3BVy4
tMOcjaEiuEY5a6qC+AxbaG5PUhWaCKhAJnai/Av0ypb05hikXnbECgbbWcm8r3PLuhyS
TJpQ==
ARC-Authentication-Results: i=1; mx.google.com;
dkim=pass [email protected];
dkim=pass [email protected];
spf=pass (google.com: domain of [email protected] designates serverip as permitted sender) [email protected];
dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=mydomain.de
Return-Path: <[email protected]>
Received: from mail.mydomain.de (mail.mydomain.de. [serverip])
by mx.google.com with ESMTPS id z35si25488994wrb.20.2017.05.25.12.21.04
for <[email protected]>
(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
Thu, 25 May 2017 12:21:04 -0700 (PDT)
Received-SPF: pass (google.com: domain of [email protected] designates serverip as permitted sender) client-ip=serverip;
Authentication-Results: mx.google.com;
dkim=pass [email protected];
dkim=pass [email protected];
spf=pass (google.com: domain of [email protected] designates serverip as permitted sender) [email protected];
dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=mydomain.de
Received: from localhost (mydomain.de [127.0.0.1]) by mail.mydomain.de (Postfix) with ESMTP id 476A7CA2F25 for <[email protected]>; Thu, 25 May 2017 21:21:04 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mydomain.de; s=mail; t=1495740064; bh=T6eVPXuCwCbaUltsFhuNXSvdEdHR+yNp0E88tVlLWVo=; h=To:From:Subject:Date:From; b=nG0IbgoWQ6jQGqZSE3YWPanvRkpLqKF/H4wIOMsQs3RBfxbFtJ1KKzFSgyvimgYTY
PEz+43mX37Uce2QqGKbKnRTPObHYII6y/pFXHivSrAaAnQ87bpMT3c4WMPAaLOeWiQ
kQnZb/UDNTrPlDVTmm/KcDP3LykKqdrPGMwOMBUA=
X-Virus-Scanned: Debian amavisd-new at mail.mydomain.de
Received: from mail.mydomain.de ([127.0.0.1]) by localhost (mydomain.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3r4vvA1sDSP5 for <[email protected]>; Thu, 25 May 2017 21:21:03 +0200 (CEST)
Received: from [192.168.10.194] (pD92B27.dip0.t-ipconnect.de [myip]) by mail.mydomain.de (Postfix) with ESMTPSA id 9B621CA2F0B for <[email protected]>; Thu, 25 May 2017 21:21:03 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mydomain.de; s=mail; t=1495740063; bh=T6eVPXuCwCbaUltsFhuNXSvdEdHR+yNp0E88tVlLWVo=; h=To:From:Subject:Date:From; b=aXQ1tHoCs3oj/Q3TyHZ6eNnpWaaFoeTFKwgBw6TrLSubj8SptLnTQ5A2Avme/nAUA
uEHeONftJ1VpKRIdK1aebBfMnPdoh6V9Qu1HLN4CaQTGKXHncGP8apoYaKxa61uRK+
yzVW+JIHcXsUBOez5MoJ4JP8sSag9F/3k1vllqlo=
To: [email protected]
From: Tim Fuchs <[email protected]>
Subject: <Email subject>
Message-ID: <[email protected]>
Date: Thu, 25 May 2017 21:21:03 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
Thunderbird/52.1.1
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
<Email message>
我看不出有什么原因会导致电子邮件被归为垃圾邮件，也许你们中有人可以帮忙。如果我能最终解决这个问题就太好了，因为这个问题已经困扰我很长时间了……
非常感谢您的帮助^.^