topic Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected" in Email

Group emails from gmail accounts rejected : "552 Spam Message Rejected"

SundayWoman814 — Wed, 31 Jan 2024 16:40:03 GMT

In the last 3 weeks, I have been notified by 2 users - both from different gmail accounts - that their group emails to me at plus.com had been rejected both with the same message "552 Spam Message Rejected".

Please can anyone advise? I am new to forums in general so may be slower to respond and need a bit of help finding my way around. Thanks.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

jab1 — Wed, 31 Jan 2024 16:49:14 GMT

Welcome to the forum, @SundayWoman814 . From my, admittedly limited, experience, that suggest that the emails contain a lot of links, and/or a lot of recipients. In both situations, the Cloudflare anti-spam filters Plusnet use can quite often get a little 'worried' about them, as both situations are classic 'spam' mail problems.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Wed, 31 Jan 2024 16:57:39 GMT

@jab1

Being a little pedantic, Plusnet uses Cloudmark for Spam filtering!!

@SundayWoman814

Without a deal of inspection it is not possible to know the precise why those emails are being rejected. In the short term, the most pragmatic measure you can take is to add the sender to your SPAM settings whitelist email addresses.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

jab1 — Wed, 31 Jan 2024 17:00:24 GMT

Sorry, @Townman - just been reading elsewhere re Cloudflare, and obviously got my clouds mixed up. 😀

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

jab1 — Wed, 31 Jan 2024 17:12:52 GMT

Just had a thought, @Townman would 'whitelisting' work if Cloudmark rejected them?

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

SundayWoman814 — Wed, 31 Jan 2024 17:35:39 GMT

@jab1

@Townman T

Thanks both - have just added both wayward addresses to my Spam Whitelist, so I'll now ask both Senders to resend... we will see. I had completely forgotten about that.

I also noted that when I did so it told me "With spam filtering turned on, emails sent from mailservers with a bad SenderBase reputation (googlemail perhaps?) will be rejected and bounced back to the sender. Emails that pass this first check are scanned and given a spam rating. What happens then depends on (your) settings."

Will let you know if that works - might take a few days.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

piersg — Wed, 31 Jan 2024 22:26:15 GMT

If it's any consolation, you're not the only one being affected by this.

The aviation club I help out with sends important safety newsletters out every month to almost 1000 pilots around the world. The latest newsletter has just gone out, with just 7 bounces - all of them with email addresses of <user>@<account>.plus.com.

<john@mxxxxs.plus.com>: host mx.avasin.plus.net[212.159.9.200] said: 552 Spam Message Rejected (in reply to end of DATA command)

The club's mail server is set up correctly with SPF, DKIM and DMARC all configured perfectly.

Emails are sent individually and personally to members, not as BCC.

It's a shame that those seven members are unfortunate enough to have an ISP with an over-zealous spam filter, and will miss out on the important information contained in the emails. Oh well.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Thu, 01 Feb 2024 02:23:03 GMT

Who is the email host for that service?

There are various issues across many platforms at present...

SPAMCOP has had Outlook 365 email servers black-balled - I have seen that result in one part of an organisation not being able to communicate with other parts of the same organisation
Hotmail.com has AWS email servers black-balled - our church's (professionally run) email service cannot send to @hotmail.com users
Google is forever refusing to accept delivery from a multitude of sources (if the delivery is to a free Gmail mailbox)

This is not specifically Plusnet having an "over-zealous" spam filter as such, for it uses Cloudmark which garners its SPAM profiling from input for the user community.

It would be worth double checking if your email server has been blacklisted by one of the many blacklisting services.

Bulk mailing services can get an inappropriate reputation from knee-jerk behaviours of communication recipients. Should someone who has subscribed to such services and subsequently determine that they no longer wish to receive the correspondence declines to use the UNSUBSCRIBE option, but instead reports these legitimate emails as SPAM, then the send will acquire a poor reputation.

That is why bulk emailers should make clear the option to UNSUBSCRIBE on EVERY bulk email to avoid unhelp SPAM reporting by receiving users.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

piersg — Thu, 01 Feb 2024 15:00:11 GMT

Hi Townman

Thank you for your comprehensive reply. My hosting company use Mailchannels https://www.mailchannels.com/ to send email. If Mailchannels had been blocked by Cloudmark then there's nothing I can do about this. However if this had happened, we would undoubtedly have had more bounces from other domains. Cloudmark claim to protect "12% of the world's email addresses". Of the 979 emails sent, we should see a much higher rejection rate for the same email. However, the ONLY provider rejecting the emails was Plusnet.

The email came from respected software CiviCRM, which adds unsubscribe links, Precedence: Bulk headers, List-Unsubscribe: headers, everything required.

I'm not here to argue with you - I know you're not plusnet - but I am rejecting your assertion that "This is not specifically Plusnet having an "over-zealous" spam filter" - because all the evidence points to this being the case. Yes, it was rejected by Cloudmark's servers. But it was rejected using parameters that would have been defined by Plusnet as part of their integration.

I have emailed the recipients individually to inform them of their ISP's rejection of the emails. It's up to them to then raise it with Plusnet. As an ex-Force9 and ex-Plusnet subscriber, I don't have any other route to Technical Support than to raise it in this forum.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

SundayWoman814 — Thu, 01 Feb 2024 15:07:26 GMT

@Townman

@piersg

@jab1

Adding the 2 email addresses to my Whitelist has partially fixed the issue: one sender has resent their original email just to me and this time the body of the email has not been truncated from header downwards so at least that has worked. The email certainly contains a lot of links - 7 or 8 of them.

But I need to wait until they include me in another bulk group email (over 50 + recipients) to find out if the Whitelisting has fully worked and that might not be for several weeks. Thanks for your help everyone.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

SundayWoman814 — Thu, 01 Feb 2024 15:11:10 GMT

@piersg

jeez....and I thought I had problems!! - thanks for this - and it is a sort of consolation!

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Thu, 01 Feb 2024 23:07:40 GMT

Be assured that the super users do have these concerns under active discussion with the business.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Fri, 02 Feb 2024 08:28:38 GMT

@piersg

That is a challenging observation - you suggest that ONLY @*.plus.com addresses are being rejected. Would you know if ALL such addresses in your list are being rejected?

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Fri, 02 Feb 2024 11:50:03 GMT

@piersg

Tests performed by another SU suggests that an email sent to their Plusnet mailbox and another mail service did score differently in the SPAM assessment, but both were delivered. To some extent individual users can determine the aggressiveness of Plusnet's SPAM profiling...

Spam protection guide - how to stop junk mail | Help | Plusnet states...

You can adjust how aggressive it is, with 5 being most aggressive and 1 the least. The spam filter is automatically set to 1.

Users also have the option of discarding obvious SPAM rather than it being delivered annotated [SPAM].

Consequently it becomes difficult to know if the service is overly aggressive across the piece, or if individuals have dialled up the SPAM aggressiveness themselves.

Therefore it would be really helpful if you were able to determine if ALL Plusnet addressees on your list are being rejected or only some.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

piersg — Fri, 02 Feb 2024 14:19:52 GMT

Hi, thanks for looking into this.

To confirm, ONLY Plusnet rejected the emails, and email sent to EVERY Plusnet subscriber was rejected.

All except 9 emails were accepted. The 9 rejections were Plusnet/F9 accounts shown in my previous post

This report shows 9 bounces, which were the PN/F9 email addresses shown in my previous post.

As a followup, when I emailed each receipient about the issues we're having with PN deliveries, many have come back with replies along the lines of "we've had previous problems with Plusnet emails going missing, here's my Gmail address that I'm using now".

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Fri, 02 Feb 2024 15:04:44 GMT

Myself and another SU are poking around this space, bringing about an update on the previous report. Now both email hosts report a spam score - which is identical.

In other words the other provider which was not flagging the content as spam, is now doing so.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

piersg — Fri, 02 Feb 2024 15:44:59 GMT

We've another mass mailing of the same type in a month - I'll report back how it went afterwards!

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

Townman — Fri, 02 Feb 2024 15:52:34 GMT

Feedback on your experience would be interesting!!

Question: how is your mass-mailing performed?

One email mass copied (by BCC) to addressees without a TO addressee
As above with a TO addressee (real or dummy)
One copy sent TO each addressee

Myself and another SU are trying to gather evidence to inform a discussion...

We have some theories, which are not well formed and might not be solidified as in doing so we might learn "too much" about how the SPAM profiling works. That would be like giving away the keys to the bank's security vault.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

MisterW — Sat, 03 Feb 2024 13:53:38 GMT

Question: how is your mass-mailing performed?

One email mass copied (by BCC) to addressees without a TO addressee

I'm fairly sure that the OP doesnt use this method BUT for anyone else who uses this simple method to send to a fixed mailing list e.g local club, investigation has shown that this is not a good idea.

An email to a single specified TO address with a newsletter attached resulted in a spam score of 0 both to a Plusnet email address and an externally hosted domain address. Sending exactly the same attached newsletter but now using the BCC field to include the two addresses ( with nothing in the TO :), resulted in a Spam score of 4.9 to the external mail address and 5.0 to the Plusnet address. Adding a valid address in the TO: field reduced the spam scores to 0 and 0.1 respectively.

Depending on how a Plusnet subscriber has their Spam settings configued , a score of 5.0 could well result in rejection.

Re: Group emails from gmail accounts rejected : "552 Spam Message Rejected"

piersg — Sat, 03 Feb 2024 16:06:43 GMT

Hi - not sure whether this was aimed at me or OP, but our emails are sent individually with the addressee in the To: field. Smaller emails from the same source are delivered successfully, but the larger (2MB) emails are bounced as SPAM.