Mail.ru accepts mail as spam?

Question

Fight against spam

There is a project whose users write messages to each other, and notification of the arrival of a new message is sent by e-mail directly to the user. Standard scheme, like on many other sites, isn't it? The vast majority of our users have postal addresses on mail.ru, list.ru, and so on.
The message looks like this:
“Full name wrote you a message on xxxx.ru.
Read: xxxx.ru/profile/messages/xxxx/ »
Innocent message. Naturally, there is no spam here at all. All messages are different, the text of the message (or subject) is different.
The problem starts when a message is sent to all users of the site (~2 emails per second, total ~50000). Starting from some threshold (approximately 20,000 letters), mail.ru rejects mail, giving error 550. Only mail.ru behaves this way. No other mail system does this. Here is the error message that comes up on EVERY email sent (each message has a different Error code, but the text is the same):

This is the mail system at host xxxxxxx.<br/>
<br/>
I'm sorry to have to inform you that your message could not<br/>
be delivered to one or more recipients. It's attached below.<br/>
<br/>
For further assistance, please send mail to postmaster.<br/>
<br/>
If you do so, please include this problem report. You can<br/>
delete your own text from the attached returned message.<br/>
<br/>
The mail system<br/>
<br/>
&lt;[email protected]&gt;: host mxs.mail.ru[94.100.176.20] said: 550 spam message<br/>
 rejected. Please visit <a href="http://mail.ru/notspam/">mail.ru/notspam/</a> or report details to<br/>
 [email protected] Error code:<br/>
 FB188D0B1941C920A91915BA1432E60E541BC971328137E499D77B1741DEFC22B0B67947ACA01B0A07FC27F77F28AA7EF28E7B1C0639918B33AF190C3B5047A9<br/>
 (in reply to end of DATA command)<br/>

When the traffic drops, the behavior of the SMTP server on mail.ru returns to its previous course.
Then again the same error, and so on.
Through the support service ( [email protected] ) solving this seemingly elementary task turned out to be a very difficult task (I made 3-4 “approaches”, spending half a year, then gave up).
The helpdesk usually works like this:

1. First, it asks me for a long time and tediously to resend either the original letter, then the error, then the service headers, then the plaintext of the original letter without headers, then with headers, then in the attachment, then without the attachment, periodically answering that the original letter is in a broken encoding (moreover that it is in the attachment !!!) or there are no service headers (despite the fact that they are present !!!). Recently, they have come to love this way of harassing users: create, they say, a new ticket by sending the text of the original letter there, you will receive a ticket id in response, and then send this ticket id to us in response to this letter. And this despite the fact that all (!!!) the necessary information was already contained in my very first appeal to the SP! In stage 1) is lost from noon to afternoon. Usually, to quickly move to the next stage, I write this:
   “What is the bitness of the encoding and what specific service headers do you need? This is exactly the letter that fell on SMTP mail.ru. In this case, I am answered with the following (see 2)
   
2. I am informed that my problem has been referred “for resolution to specialists”.
   
3. The next day, the following is reported: “The letter you sent us successfully passes our filters. Make sure that the filters worked specifically for this email. If the error repeats again with another letter, send the letter that you cannot send with the full text of the error that occurs when sending it.
   Indeed, on the one hand, the letter passes the filters, because it is obvious that it is not spam, and without “transfer to specialists”, on the other hand, it does not pass, because the problem is not in the letter itself, but in the number of letters or in the frequency of their sending. The content of the letter in this case does not affect in any way, which could be guessed from the hashcode from the very first call and skip steps 1), 2), 3).
   
4. If you try to convey this idea to a support, he answers like this:
   “Hello.
   You have exceeded the maximum number of messages sent.
   To organize the mailing of letters to a large number of addresses, you can
   use our service - content.mail.ru/ "
   This usually ends the theater of the absurd, because there is nothing to answer. Using content.mail.runot included in our plans (although, probably, according to the support service, google, yahoo, yandex, ..., of course, use it, because they send mail tens, hundreds, thousands of times more intensively than us). Information about what specifically in my case is exceeded: the frequency of sending letters or the total number per unit of time and by how much is exceeded, the support does not have. I once made an attempt to find out about the specific limit numbers from the support, to which I received the following answer:
   “We allow:
   - from one IP address - 45 letters in the first minute and 3 letters in the next.
   - from one mailbox - 15 letters per minute, then you can only send 1 letter per minute.
   Amazing! If this were the case, no mail would go anywhere at all (what “next” minutes are is also unclear. For life, perhaps, 3 letters per minute?). S.P. apparently thinks that I send mail to mail.ru through the mail.ru web interface itself.
   

What needs to be done to solve this problem? It would seem that he took Error code FB188D0B1941C920A91915BA1432E60E541BC971328137E499D77B1741DEFC22B0B67947ACA01B0A07FC27F77F28AA7EF28E7B1C0639918B33AF190C3B5047A9 and sent it to programmers. They looked at why it occurs and informed the support, and then me. But for some unknown reason, this does not happen.
Dear habrausers! Help! The support service is impenetrable! I also sent soap to the mail.ru directorate, no answer. It is necessary to “cure” either mail.ru or our project at all costs! Offers "Reduce the frequency of sending emails" are not accepted. Accepted: “Add such and such a header to the letter”, “Type in an SPF record” (already spelled out), etc.

Answer 1

The content of the message does look like spam. The number of such messages, which are very similar to each other, can also make the robot think of dishonesty. If I were you, I would insert the received message directly into the text of the letter. In this way, you diversify notifications in the eyes of antispam solutions and make it convenient for people who do not have to go to your site to see messages like “ok, we’ll do it” or “bye”.
Still down would be to add links to the unsubscribe / notification settings pages.

Answer 2

Unfortunately, the error code is not always enough to determine the reason for the blocking. That is why the support asks to send the original letters. The scheme is not very convenient, we are working on simplifying it.
As far as your email is concerned, blocking with the 5xx error code is not a blocking based on the number of emails sent, it is a blocking based on the content of the letter only (otherwise you would get errors with the 4xx code). A large number of complaints are received on the blocking letter you provided (users click the "This is spam" button).
The problem can be solved by adding the ability to quickly unsubscribe from notifications to each letter (and this is one of the requirements of the document that you cited - “Technical and administrative requirements for sending emails to Mail.Ru”).

Answer 3

And why, when two users communicate, a message is sent to all users of the site? It is probably worth first of all to revise the notification algorithms so that when two users communicate, notifications are not sent to everyone.
According to your conditions, you send out a full mailing list for 25,000 seconds, which is 6.9 hours, and you claim that at the third hour the mail starts blocking you? It is not completely clear whether you exceed the limit of letters per domain or per IP address of the smtp server, check this question with the mail.
Companies Google, Yandex and others in no case use content.mail.ru
The simplest thing that comes to mind is to send mail from two different servers.

Answer 4

Weird. Earlier (several years ago) I also faced impenetrability of their support.
But recently we (the project in which I am currently working) had this 550th error, without much hope they wrote to support and, to incredible surprise, the problem was solved the very next day. They didn’t say exactly how (we didn’t ask), apparently they added it to the whitelist ... During the decision, they asked to show headings and give examples of letters, they provided everything.
Yes, we are a really large online store. It is possible that requests from different resources are responded to in different ways ...

Answer 5

I constantly do mass mailings, there are a lot of mail.ru mailboxes among the recipients - I haven’t seen a blow-up for a very long time. Previously, there was the same problem (thumps due to "spam"), I wrote to them, butted for a long time, in the end they gave a couple of tips on what to tweak and everything worked like clockwork, for 3 years now not a single beat is not relevant.
Twisted a lot of things, encoded headers in base64, spf, mime-encoding, plain / text-part, list-unsubscribe, a link to prohibit mailing at the end of the letter - this is what I remember right away.

Answer 6

By the way, we have the same problem today. We send through an external service.

Answer 7

Mail.ru is beautiful :/ They periodically manage to block the next letter in correspondence as spam. In this case, the only advice they can give is to add a link to unsubscribe in the body. What, in the stump, unsubscribe if this is a regular correspondence initiated by _their_ user?! But it is impossible to convey such simple things to support. They apparently have a template - they looked at the body of the problematic letter, there is no "unsubscribe" link - the problem is found, we write the answer "insert!" and close the ticket :/

Answer 8

Actually, mail.ru has a document that regulates their soap acceptance policy: help.mail.ru/mail-help/rules/technical. I am familiar with this document and comply with its reasonable requirements.
Questions:

1. How valid is this document? Why, generally speaking, the hell should I insert the phone number of my organization into a letter like “You received a new message on the site ... Organization such and such. Such an address. The phone is so-and-so.
2. How strictly do they follow the established rules?
3. "... getting messages into Mail.Ru spam traps affect the sender's reputation" - how to find out your reputation?

Answer 9

Wrote a post on this topic habrahabr.ru/post/223149