Outgoing SMTP server's spam filter is hypersensitive

[#1]

I forwarded a delivery notification from Amazon and relay.plus.net bounced it as spam - not very helpful.

Talking to relay.plus.net on Sun, 29 Sep 2024 16:49:45 +0100
>>> DATA
<<< 552 [xxxx] message rejected due to spam or virus. If you believe this is in error please login to your portal or contact your ISP support team.

What would logging to my portal achieve?

The same has happened with a service ticket from another online shop. Both perfectly innocuous. Dial down the spam filter's sensitivity!

[#2]

@SilverE Unless it can be proved what has upset the filter, it is difficult to 'dial it back'. Just for interest, if I  am forwarding emails such as those you describe (or any, to be more correct), I always remove the original headers, and have never had any issues with such forwarded mails being flagged.

[#3]

Don't get your point about removing headers, I'm not forwarding as an attachment, it's simply the message body that's forwarded. And when I removed Amazon's body text - which arrived perfectly happily - my added message got sent no problem.

This has happened twice in the last month, and never before since I started using Freeserve in 1998. Something has been dialled up and needs dialling back. If PlusNet wants to inspect the offending mail I can PM it.

[#4]

I don't forward as an attachment either - just the message itself, but without the original senders address, return address, email title &c.. I have always done this, so I don't know what happens if I include them, but as you are the first to have noticed this, AFAIK, maybe it is your email program or something.

I have forwarded emails from Amazon, other online retailers, rail companies and other entities, and never had an issue.

And yes, I use relay.plus.net.

[#5]

I am using Outlook (classic) and I surmise that PlusNet handles a fair few emails sent from that program so I doubt if that it the problem. I don't understand your practice of deleting the attribution headers.

I'm happy that you haven't had your emails rejected as spam but that doesn't mean that mine were not.

[#6]

Although this issue only seems to affect you - no-one else has reported it - it is a bit difficult for me to give further advice. The program you use for sending is irrelevant, it is the content which causes the rejection. I delete the attribution headers for a couple of reasons (1) those I forward to don't need them (2) It reduces the payload, and (3) It potentially removes a 'false positive' for Cloudmark to pick up.

@Townman  / @MisterW  - any insights, this is a bit above my pay grade?

[#7]

John,

Your assessment is spot on.  There is going to be something in the forwarded email which is triggering the spam flags.  It is not unusual for spam prevention systems to inhibit the forwarding of content which has been received - it stops the re-propagation of content which might have been found to be suspicious AFTER it was received.

Such is the characteristic of real-time learning systems ... something gets sent (usually in bulk) and recipients start flagging it as spam (rather than unsubscribing from the source) ... and at some threshold point the content is deemed to be spam ... and thereby be blocked both inbound and outbound.

Spam management is not and never will be black and white - people complain when it blocks and the complain when it does not should it be "dialled down" whatever that might mean (as that is not how spam filtering works).

There is the option of modifying an individual's filtering aggressiveness in the use portal, to the point of turning it off altogether.  Though I do not know if that applies to outbound emails, as I think the outbound filtering is designed to protect the reputation of Plusnet's email servers and cannot be 'adjusted' on an individual basis.