Emails to plus.com email addresses rejected 'Spam message rejected'

[#1]

I have the same problem as https://community.plus.net/t5/Email/Emails-to-plus-com-email-addresses-rejected-Spam-message/td-p/16... , so I am posting here so I can PM as advised in that topic

[#2]

Hi @cameo 

A warm welcome to the forums.

The same PROBLEM (emailing from the same school service) or the same SYMTONS - something being sent is being rejected as spam?

Can you please provide some details of the issue?  Are there any specific links in the emails?

Who is the sending email service?  is there hard fail SPF configured?

In the first place, posting the 522 signature here and or any URLs in the emails, might be enough to progress this for you.

[#3]

OK, same SYMPTOMS (multiple messages to all Plusnet email addresses on different occasions consistently rejected as spam on the last several occasions we have tried, when they have previously all been accepted, with no significant changes). No other provider bounces these. There is no reason plus.net should be bouncing them. SPF, DKIM and DMARC are all set up correctly. We are not on any major public block list.

As I said, the only reason  I was posting here was to be able to send a private message. That is not possible, apparently, without posting publicly first. The details contain private information and the solution will need action at the plus.net end, it is not something I can control. 

[#4]

Sometimes, these can be replicated / sorted with the scantest of information.

This is not a matter of Plusnet rejecting them, but rather the industry leading Cloud Mark anti-spam platform, which learns what looks like spam from a vast community of users.  There are trends of people marking emails they have subscribed to as spam, rather than unsubscribing, which results in the sender being inappropriately blackballed.

This needs help from 2nd line support ... will see if I can get direct engagement for you.

[#5]

@Gandalf  / @MatthewWheeler  / @TheMightyAJ 

Can someone on the front line please grab this one?  Thank you.