[MlMt] Query about not receiving mail

[Bill Cole]

On 25 Sep 2018, at 7:02 (-0400), Annamarie wrote:

> Hi
>
> This isn't really a MM tech question but it's an email question and 
> maybe someone on this list has some insight...
>
> To wit
>
> I emailed 15 people and sent as a BCC so as not to share their emails 
> with each other. Discovered yesterday that two of them hadn't received 
> the mail. The addresses are correct (I've used them, copying and 
> pasting from the actual email I sent), they are in the middle of the 
> list. The mail didn't go into spam - it just didn't get there as far 
> as I can tell.
>
> Why would that happen? Any ideas?

I blame the race to the bottom in the business of providing mailboxes...

More specifically, this is a thing that some mail providers will do 
because they've chosen to economize on their capacity to do mail 
filtering and deliverability decisions "live" during the SMTP 
conversation rather than simply queueing messages that they may 
eventually decide not to deliver. Usually that's due to flaky spam 
filtering, but there can be other causes. The biggest offenders in this 
are Microsoft (with their free services being *MUCH* worse about it than 
their paid Office365) and Yahoo. Google is much less likely to silently 
drop legitimate messages at the price of being the most opaque about why 
messages land in their 'Spam' folders. Beyond the 800-pound gorillas of 
email there are many smaller mail systems who have made similar choices, 
to sacrifice robustness for convenience by dropping mail silently rather 
than risk misdirected 'backscatter' from deferred filtering. The 
specific reason your mail is being caught by filtering that ends up just 
dropping messages is site-specific, case-specific, and in some cases 
(e.g. Microsoft) literally unknowable because the systems doing it are 
based in complex "machine learning" and don't have fixed criteria.

TL;DR version: Email is not a robustly reliable communication medium and 
is less so today than it has been in the past, due largely to the 
triumph of "free" mailboxes.




-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Available For Hire: https://linkedin.com/in/billcole