Mail from certain domains not delivered to my outlook.com address

Topic

I have a Microsoft 365 subscription and my main email address is “@outlook.com” – so I assume my mail server is hosted by Microsoft.

Email from a few mail domains (notably “tesla.com” and “d.malwarebytes.com) never gets delivered.   I’ve checked all my outlook clients (web, phone, desktop), turned off all rules, added the specific domains to the “safe senders and domains” list specifically – none of this helps.

Is there anything else to investigate?   When I’ve reported the non-delivery to the senders they point the finger back at Microsoft.   And when I’ve tried to engage Microsoft support, the finger is pointed back at the senders.

Replies

All email providers check email when it arrives. If the email does not have the right authentication the email will be silently dropped and you will never see it.
This is a 2 way thing, the email sender must have authentication, the receiver must implement the checks so that it allows “not quite right, but probably OK” email through. It seems MS have a higher bar / crappy implementation.

cheers, Paul

Thanks. I was afraid it was something like this (which I can’t mitigate.)    I’ll change these subscriptions to another of my email addresses.

Although you might find the tesla email never gets through. 

cheers, Paul

Tesla emails do get through to my gmail address.

Basically, SOL until and if Microsoft fixes Exchange Server fussiness.

Microsoft has recently announced increased security for Outlook.com email. See Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders | Microsoft Community Hub for details. Although the article says enforcement does not start until May 2025, they may have already started phasing it in. I read somewhere that I can’t find at the moment that the safe sender list and rules have no effect on this.

--Joe

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Paul T

You can find several articles discussing these changes in the results at microsoft email sender requirements – Search

--Joe