From address doesn't meet the authentication requirements defined for the sender

[#1]

Does any provider other than Plusnet have a sub-domain in the email address for normal users? I've looked through my mailing lists and I can't find one, but if there is, are they experiencing the same problems emailing to MS-related addresses as we are?

[#2]

Plusnet didn't have a problem until MS  decided to 'strengthen their anti-spam protocols'.

[#3]

@Townman      Yes Plusnet is my ISP.  I am intrigued as to why the mere presence of a second recipient of any email provider causes the microsoft recipient to fail. 

[#4]

@Silver-Codger 

It’s not difficult to advance a theory to cover your particular scenario:

MS receives the email destined for its addressee but also detects that:

1. it is being sent to more than one address; and
2. the sending address has the structure you@youraccount.plus.com

causing MS to suspect that this could be a bulk sender and to apply more strict criteria, resulting in the email being rejected.

@jab1 

Until we know otherwise, it is entirely possible that MS deciding to 'strengthen their anti-spam protocols' has uncovered a latent flaw in Plusnet’s approach - that is why I asked the questions in #421.

[#5]

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@abitpedantic wrote:

@jab1 

Until we know otherwise, it is entirely possible that MS deciding to 'strengthen their anti-spam protocols' has uncovered a latent flaw in Plusnet’s approach - that is why I asked the questions in #421.

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Unless you can expand on the 'latent flaw' suggestion, personally I would discount that theory. I forget just how long the Plusnet 'approach' has been in existence without issue until MS decided  to start getting 'strict', but I suspect it is long enough for it to have shown up before now.

[#6]

The answer is perhaps 20+ years.

In the same period a number of previously common email practices have been deprecated and are no longer permitted.

[#7]

@PhilipHeyes You are correct as regards the time period, however, the use of sub-domains is still permitted, unless government departments/agencies and many companies are persisting with deprecated/ no longer permitted practices.

[#8]

What is permitted, and what is currently being accepted are not always the same thing.

[#9]

So, you are saying sub-domains are no longer permitted? If so, can you please point me in the direction of the regulation?

[#10]

@abitpedantic   I agree entirely with your proposition regarding the failure to deliver multiple address emails to an MS related recipient.

@Townman   Do we know if this scenario has been advanced to MS?  At the risk of mixing my metaphors I get the impression there is a Chinese wall of silence between PN & MS and that MS is a black hole of information.  Unfortunately it is we Plusnet users that are suffering the consequences!  Time to bang a few heads together!!

[#11]

I'm no expert, but may I add another twist?
I use AWS SES as my SMTP outgoing server, I also find email to Outlook.com addresses are not delivered.
This maybe suggests the (sub)domain is looked up by the receiving mail server, and MS rejects.

[#12]

If your address is a Plusnet one, then using other than the Plusnet relay server is likely to upset Microsoft.

[#13]

@jkg 

If you are sending you@account.plus.com via AWS SMTP servers I am astounded that anything is being delivered to MS platforms at all.

Prior to the draconian bulk sender rules being imposed, MS platforms required SPF or DKIM.  The rule change requires BOTH to be configured.  Previously this space on had DKIM and DMARC configured at the plus.com level.

SPF has been added; SPF always 'lives' at the sending domain level, in this case account.plus.com.  SPF designates the servers which are authorised to send email on behalf of the domain.  AWS SMTP servers are not authorised to send email on behalf of *.plus.com. The failure action is ~all (soft fail) which essentially means receiver decide - drop or deliver with SPAM warning.

However, the failure experiences being reported relate to DKIM, not SPF.

[#14]

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@jab1 wrote:

So, you are saying sub-domains are no longer permitted? If so, can you please point me in the direction of the regulation?

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So, no response then, @PhilipHeyes ?

[#15]

Dear John ( jab1 ),

In my earlier post I did not state or infer sub-domains are no longer permitted.

You introduced that idea.

Have super evening.

Philip