Email still dropping into SPAM after SPF etc.; why? - email

Question

I've automated the sending of my e-mails in PHP using PHPMailer:
$mail->isSMTP();
$mail->SMTPAuth = true;
$mail->Host = $host; // verified with my host
$mail->Port = 465;
$mail->Username = 'mymail#example.com'; // verified with my host
$mail->Password = 'mypassword'; // verified with my host
$mail->SMTPSecure = 'ssl';
$mail->SMTPAutoTLS = true;
$mail->setFrom( 'mymail#example.com', 'This is the Header of the E-Mail' );
$mail->addAddress( 'recipientsmail#hisexample.com', '' );
$mail->isHTML( true );
$mail->Subject = 'This is the Subject of the E-Mail';
$mail->CharSet = 'UTF-8';
$mail->Body = 'HTML Content of the E-Mail';
$mail->send();
$mail->SmtpClose();
First, many emails sned via this script dropped into the SPAM of my clients. I checked back with the host, and they helped me to add an SPF record:
Type: TXT
TTL: 300
Value: "v=spf1 redirect=shared_host_mail_server"
This improved the non-spam delivery rate a lot, but especially for gmail, significant portion still drops into spam. An example of the source of an email that dropped into the email spam is:
Delivered-To: my.secret#gmail.com
Received: by 2002:a17:906:f12:0:0:0:0 with SMTP id secret;
Mon, 21 Mar 2022 06:58:32 -0700 (PDT)
X-Google-Smtp-Source: ABdhPJz6F29tChwOYHMaPAlJC0D9QTnj/JMhktHDZEuWjHBWU7x/ZdnkZS7MccoMwSxrMjrZec73
X-Received: by 2002:a5d:4ad2:0:b0:203:d56d:9c82 with SMTP id secret;
Mon, 21 Mar 2022 06:58:30 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1647871110; cv=none;
d=google.com; s=arc-20160816;
b=K3FgBLtaiFZEsUAPiR2dBpquBEVEKZ2A82PhG+nCN7I7NRTxE8KDueotg3pndOeoQQ
IaCxIO8uYvkka1BmdSz8RuL0H/+OuXh+UMTpuy5tnhteTy3IR5Ub8vfl2eCl5AsCUj1R
ZLkysapUMphblFlZnSz4JObVz0jgN8P4uAE39ObN1YVpLZ9bT//BXuVjyYbKuHyhDUoP
AnZ+cjey7I4dyuvaaUWyrIMC7xEnLratGSN4mtIBWhEuWrMokXZtnbVZMHtNh+W7d5d1
HGmWzWdnWftGZJFI8e2fnNSRosRE0pwzblCNAkGd+PmJHOEDlq5pmaLla1I9yZpxZa3z
dx4w==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
h=content-transfer-encoding:mime-version:message-id:subject:from:to
:date;
bh=NCbhFSalLdDA2HAK57ps0Gy6VG+hTVJz6G8PW0XPkpo=;
b=TuIDSDjGMJOISTWTkb8iaOA1qJ3QYFLU6adhuG2kbyzpICBc0EC5MNvkGDWcEH9znp
UjYJ0Uug/79c6ZSzLaXuv3THIwuO7MJTuM5r7YXTbFvGnwNlO/Qc1xO/bo63rIN1ZS8y
aKRtpzjO0hMqjxlbltnZPcNice0DqZZcX0BlaU8kkgKFGw96vpBj9A0ZZbAyvmK2Lyws
oGYdKUmcOhosxXIxM8AAu1JVtM0bI2EncDo5UvwBIXVitvgcmORTfS1u3RBsKakk9tXI
bBCer6hxpjjn+hRxMOsdjqFdLa0EIIxnuW/z05Yh4CYSPBi1RZM0q/hWCMPvjDqBRFY5
8vVQ==
ARC-Authentication-Results: i=1; mx.google.com;
spf=pass (google.com: domain of secret.sender#example.com designates 2a00:d70:0:e::313 as permitted sender) smtp.mailfrom=secret.sender#example.com
Return-Path: <secret.sender#example.com>
Received: from host_out_mail_server (host_out_mail_server. [2a00:d70:0:e::313])
by mx.google.com with ESMTPS id secret
for <my.secret#gmail.com>
(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
Mon, 21 Mar 2022 06:58:30 -0700 (PDT)
Received-SPF: pass (google.com: domain of secret.sender#example.com designates secret_ip as permitted sender) client-ip=secret_ip;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of secret.sender#example.com designates secret.sender#example.com as permitted sender) smtp.mailfrom=secret.sender#example.com
Received: from [10.0.2.46] (helo=host_mail_server) by host_out_mail_server with esmtps
(TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.94.2 (FreeBSD)) (envelope-from <secret.sender#example.com>) id 1nWIYH-0000QW-8D for my.secret#gmail.com; Mon, 21 Mar 2022 14:58:29 +0100
Received: from other_host_server ([2a00:d70:0:b::2:10] helo=example.com) by host_mail_server with esmtpa (Exim 4.95 (FreeBSD)) (envelope-from <secret.sender#example.com>) id 1nWIYG-00010j-7w for my.secret#gmail.com; Mon, 21 Mar 2022 14:58:29 +0100
X-Authenticated-Sender-Id: secret.sender#example.com
Date: Mon, 21 Mar 2022 13:58:28 +0000
To: my.secret#gmail.com
From: Werbe - Anfrage <secret.sender#example.com>
Subject: Bekanntmachung
Message-ID: <secret#example.com>
X-Mailer: PHPMailer 6.5.0 (https://github.com/PHPMailer/PHPMailer)
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="b1_ciluFWHutVghcyNH2SHrnSBIhFM0AuGhsYu8JefeYks"
Content-Transfer-Encoding: 8bit
--b1_ciluFWHutVghcyNH2SHrnSBIhFM0AuGhsYu8JefeYks
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE html>
<html lang=3D"de" xmlns=3D"http://www.w3.org/1999/xhtml" xmlns:o=3D"urn:sch=
emas-microsoft-com:office:office">
<head>
<meta charset=3D"UTF-8">
<meta name=3D"viewport" content=3D"width=3Ddevice-width,initial-scale=3D1=
">
<meta name=3D"x-apple-disable-message-reformatting">
<title></title>
<!--[if mso]>
<style type=3D"text/css">
table {border-collapse:collapse;border:0;border-spacing:0;margin:0;=
}
div, td {padding:0;}
div {margin:0 !important;}
</style>
<noscript>
<xml>
<o:OfficeDocumentSettings>
<o:PixelsPerInch>96</o:PixelsPerInch>
</o:OfficeDocumentSettings>
</xml>
</noscript>
<![endif]-->
<style type=3D"text/css">
/* CLIENT-SPECIFIC STYLES */
body,
table,
td,
a {
-webkit-text-size-adjust: 100%;
-ms-text-size-adjust: 100%;
}
table,
td {
mso-table-lspace: 0pt;
mso-table-rspace: 0pt;
}
img {
-ms-interpolation-mode: bicubic;
}
/* RESET STYLES */
img {
border: 0;
height: auto;
line-height: 100%;
outline: none;
text-decoration: none;
}
table {
border-collapse: collapse !important;
}
body {
height: 100% !important;
margin: 0 !important;
padding: 0 !important;
width: 100% !important;
}
/* iOS BLUE LINKS */
a[x-apple-data-detectors] {
color: inherit !important;
text-decoration: none !important;
font-size: inherit !important;
font-family: inherit !important;
font-weight: inherit !important;
line-height: inherit !important;
}
/* MOBILE STYLES */
#media screen and (max-width: 600px) {
.img-max {
width: 100% !important;
max-width: 100% !important;
height: auto !important;
}
.max-width {
max-width: 100% !important;
}
.mobile-wrapper {
width: 85% !important;
max-width: 85% !important;
}
.mobile-padding {
padding-left: 5% !important;
padding-right: 5% !important;
}
}
/* ANDROID CENTER FIX */
div[style*=3D"margin: 16px 0;"] {
margin: 0 !important;
}
</style>
</head>
<body style=3D"margin: 0 !important; padding: 0; !important; word-spacing: =
normal; background-color: #ffffff;" bgcolor=3D"#ffffff">
<div style=3D"display: none; font-size: 1px; color: #fefefe; line-height: 1=
px; font-family: Open Sans, Helvetica, Arial, sans-serif; max-height: 0px; =
max-width: 0px; opacity: 0; overflow: hidden;">
This is the text of the preheader
</div>
<table role=3D"presentation" border=3D"0" cellpadding=3D"0" cellspacing=3D"=
0" width=3D"100%" bgcolor=3D"#d3d3d3" style=3D"background: #d3d3d3;">
<tr>
<td align=3D"center" valign=3D"top" width=3D"100%" style=3D"padding=
: 0;">
<!--[if (gte mso 9)|(IE)]>
<table role=3D"presentation" align=3D"center" border=3D"0" cell=
spacing=3D"0" cellpadding=3D"0" width=3D"600">
<tr>
<td align=3D"center" valign=3D"top" width=3D"600">
<![endif]-->
<table role=3D"presentation" align=3D"center" border=3D"0" cell=
padding=3D"0" cellspacing=3D"0" width=3D"100%" style=3D"max-width:600px;">
<tr>
<td align=3D"center" valign=3D"top" style=3D"padding: 0; border-left: 1=
px solid #000000; border-right: 1px solid #000000; border-bottom: 1px solid=
#000000;">
<img src=3D"https://example.com/mail_visual.png" wi=
dth=3D"600" border=3D"0" alt=3D"" style=3D"display: block; width: 100%; hei=
ght:auto;" class=3D"img-max"/>
</td>
</tr>
<tr>
<td align=3D"left" valign=3D"top" bgcolor=3D"#ffffff" style=3D"backgrou=
nd: #ffffff; padding: 15px 30px 30px 30px; font-family: Open Sans, Helvetic=
a, Arial, sans-serif; border-left: 1px solid #000000; border-right: 1px sol=
id #000000;">
<h4 style=3D"font-family: Open Sans, Helvetica, Arial, sans-serif; =
font-size: 17px; line-height: 23px; color: #000000;">Salutation</h4>
<p style=3D"color: #000000; font-family: Open Sans, Helvetica, Aria=
l, sans-serif; font-size: 16px; line-height: 22px; margin: 0;">Sample Context</p>
</td>
</tr>
<tr>
<td align=3D"center" valign=3D"top" bgcolor=3D"#13aff0" style=3D"backgr=
ound: #13aff0; padding: 10px 30px; font-family: Open Sans, Helvetica, Arial=
, sans-serif; border-left: 1px solid #000000; border-right: 1px solid #0000=
00; border-top: 1px solid #000000;">
<h5 style=3D"font-family: Open Sans, Helvetica, Arial, sans-serif; fo=
nt-size: 16px; line-height: 24px; color: #ffffff; margin:0 0 5px 0;">Domai=
n</h5>
<img src=3D"https://example.com/icons/first.png" width=3D"107" he=
ight=3D"40" border=3D"0" alt=3D"first" style=3D"display: bl=
ock; border: 0px; color: #999999; font-family: sans-serif; font-size: 18px;=
" />
<p style=3D"margin:7px 0 15px 0;"><a href=3D"mailto:secret.sender=
#example.com" target=3D"_blank" style=3D"text-decoration: none; color: #fff=
fff; font-family: Open Sans, Helvetica, Arial, sans-serif; font-size: 16px;=
line-height: 16px;">secret.sender#example.com</a></p>
<p style=3D"margin:0 0 14px 0;"><a href=3D"https://example.com" targe=
t=3D"_blank" style=3D"text-decoration: none; color: #ffffff; font-family: O=
pen Sans, Helvetica, Arial, sans-serif; font-size: 16px; line-height: 16px;=
">www.example.com</a></p>
<!--[if (gte mso 9)|(IE)]>
<table role=3D"presentation" align=3D"center" border=3D"0" cellspacin=
g=3D"0" cellpadding=3D"0" width=3D"157">
<tr>
<td align=3D"center" valign=3D"top" width=3D"157">
<![endif]-->
<table role=3D"presentation" align=3D"center" border=3D"0" cellpaddin=
g=3D"0" cellspacing=3D"0" width=3D"100%" style=3D"max-width:157px;">
<tr>
<td style=3D"padding:0;">
<a href=3D"https://www.instagram.com/companylink/" target=3D"_blank=
" style=3D"text-decoration: none;"><img src=3D"https://example.com/icons/In=
stagram.png" alt=3D"Link for Instagram Channel" width=3D"30" height=
=3D"30" style=3D"height:auto;display:block;border:0;" /></a>
</td>
<td style=3D"padding:0 0 0 15px;">
<a href=3D"https://www.linkedin.com/company/name" target=3D"=
_blank" style=3D"text-decoration: none;"><img src=3D"https://example.com/ic=
ons/LinkedIn.png" alt=3D"Link for LinkedIn Channel" width=3D"30" he=
ight=3D"30" style=3D"height:auto;display:block;border:0;" /></a>
</td>
<td style=3D"padding:0 0 0 15px;">
<a href=3D"https://twitter.com/companyname" target=3D"_blank" style=
=3D"text-decoration: none;"><img src=3D"https://example.com/icons/Twitter.p=
ng" alt=3D"Link for Twitter Channel" width=3D"30" height=3D"30" sty=
le=3D"height:auto;display:block;border:0;" /></a>
</td>
<td style=3D"padding:0 0 0 7px;">
<a href=3D"https://www.facebook.com/compnyname" ta=
rget=3D"_blank" style=3D"text-decoration: none;"><img src=3D"https://domai=
n.com/icons/Facebook.png" alt=3D"Link for Facebook Channel" width=
=3D"30" height=3D"30" style=3D"height:auto;display:block;border:0;" /></a>
</td>
</tr>
</table>
<!--[if (gte mso 9)|(IE)]>
</td>
</tr>
</table>
<![endif]-->
</td>
</tr>
</table>
<!--[if (gte mso 9)|(IE)]>
</td>
</tr>
</table>
<![endif]-->
</td>
</tr>
</table>
</body>
--b1_ciluFWHutVghcyNH2SHrnSBIhFM0AuGhsYu8JefeYks
Content-Type: application/octet-stream; name=QR_DE.pdf
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=QR_DE.pdf
--b1_ciluFWHutVghcyNH2SHrnSBIhFM0AuGhsYu8JefeYks--
I don't see the problem in this e-mail source extract / the reason why it drops into spam; does anyone of you?
I then checked back with the host about the particular gmail problem, and they recommended me to change my spf record to:
"v=spf1 include:_spf.google.com redirect=shared_host_mail_server"
But I feel that this is wrong / is only necessary if you want to send emails from your domain across gmails server's, or am I wrong?
Anyway, any suggestions on how I can improve the result? I don't use DKIM / DMARC so far, because my host does not support DKIM signing. Is it a good idea to try to implement DKIM via PHPMailer in this case / is it even possible to do so if the host server does not support DKIM natively?
Thanks in advance for any help!
P.S.: I did this test and the result was:
This goes for both mentioned versions of the SPF. However if I check in other tools as mail-tester or email on acid, the SPF is valid. Just FYI