Legit mail regarded as spam

1

Currently taking eM Client for a test drive (again), and was puzzled that virtually all of my test mails ended up in my spam box. Searched the forum, found various folks facing similar issues, and the standard reply was: It’s not eM Client - must be your own server labeling it as spam.

True.

Checked this and can confirm that it was indeed my server regarding the mail as spam - but that is because the mail send via eM Client is different from the mail sent via any other MTA. Turns out that all the mails I sent via eM Client were detected as bulk mail by dcc-servers.net.

DCC_CHECK Detected as bulk mail by DCC (dcc-servers.net)

Odd. I took a look at the source code, and while I’m not a super expert in the field, I did notice that an “empty” mail sent via eM Client isn’t really empty, but is full of all kinds of code:

--------=_MB6B31852F-A069-4520-BA25-3CD99F5FA0EE
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: quoted-printable


--------=_MB6B31852F-A069-4520-BA25-3CD99F5FA0EE
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable

<html><head>

<style id=3D"css_styles">=20
blockquote.cite { margin-left: 5px; margin-right: 0px; padding-left: 10px;=
 padding-right:0px; border-left: 1px solid #cccccc }
blockquote.cite2 {margin-left: 5px; margin-right: 0px; padding-left: 10px;=
 padding-right:0px; border-left: 1px solid #cccccc; margin-top: 3px; padding=
-top: 0px; }
a img { border: 0px; }
table { border-collapse: collapse; }
li[style=3D'text-align: center;'], li[style=3D'text-align: center; '], li[s=
tyle=3D'text-align: right;'], li[style=3D'text-align: right; '] {  list-sty=
le-position: inside;}
body { font-family: 'Segoe UI'; font-size: 12pt; }
.quote { margin-left: 1em; margin-right: 1em; border-left: 5px #ebebeb soli=
d; padding-left: 0.3em; }
a.em-mention[href] { text-decoration: none; color: inherit; border-radius:=
 3px; padding-left: 2px; padding-right: 2px; background-color: #e2e2e2; }

 </style>
</head>
<body>

</body></html>
--------=_MB6B31852F-A069-4520-BA25-3CD99F5FA0EE--

1200+ characters is really a LOT of stuff for an empty mail, and it seems like DCC is regarding it as mass spam mail in its own right.

Some more testing… My thunderbird is set to send plan text mail. When I switch to html, the html code is only 160 characters long:

<!DOCTYPE html>
<html>
  <head>

    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
  </head>
  <body>
    <br>
  </body>
</html>

Trying to spring the spam trap: Sending an empty html mail via Thunderbird will end up in spam as well, while entering three random characters will individualize it enough so it arrives just fine.

Since the HTML in eM Client is that long, however, this won’t do: In my tests, a three letter message had it reliably classified as spam, while four letters were fine.

I’ve now set eM Client to send new mail as plaintext so this isn’t going to bug me again, just pointing it out in case others run into the same issue and are as puzzled as I am.

2

Currently taking eM Client for a test drive (again), and was puzzled that virtually all of my test mails ended up in my spam box.

I suspect there is something “in the subject or the body of the emails” that the DCC mail servers detect as spam. The default eM Client HTML code doesn’t normally get marked as spam.

I’ve now set eM Client to send new mail as plaintext so this isn’t going to bug me again, just pointing it out in case others run into the same issue and are as puzzled as I am.

Alot of mail servers can automatically mark blank html emails with only a subject as spam due to they can be a eg: a sign of a dangerous email or a phishing email etc. So thats probably why your DCC Servers mark it as spam when sending blank HTML emails compared to Plain text. They probably have stringent spam policies. Suggest to contact their technical support for help.

My own IMAP account mail servers “will allow sending eM Client HTML blank emails with only a subject”, but i normally don’t send blank emails to avoid possibly being marked as spam.

3

Cyberzork, I genuinely appreciate you trying to be helpful, but I feel you should not reply to topics you clearly know nothing about with statements that suggest otherwise.

I never said that dcc-servers.net detected anything as spam - I said they identified it as bulk mail. I described what I did and anyone who actually knows what dcc-servers do and uses them to calculate spam score will easily be able to confirm my findings. Let leave it there.