e-mail to msn.com bounces due to missing DMARC

I have just one person with an MSN.COM address. I still get the DMARC error today. There is Diagnostic information for administrators included in the bounce message I can provide to you if that is of value.

I appreciate the info. Are these emails you're sending being sent directly from our Xfinity Connect email portal, or a third-party client service such as Outlook or Apple's native mail service?

I normally use Thunderbird to send through Comcast's servers.

I just tried a test message from the Comcast web portal and I received a similar DMARC error message.

I appreciate you testing it on both! Based on the error messaging you're receiving, and the fact that you're getting the same error from the Xfinity Connect portal would definitely indicate there's some sort of filter set up from the recipients MSN side that isn't allowing the message to be received.

If this is the only email address that's populating that rejection error for you, you may want to test sending that same recipient a message from a second email if you can, or even ask if the recipient recently changed any of their email filtering settings. If this is an email address you've messaged before with no issue, especially recently, then there would be no reason why the message wouldn't be properly authenticated once sent as it's always been prior.

The recipient says they have no filter rules and even claims they don't know how to setup a filter rule. After my last post I used my Gmail account to send a message and the recipient confirmed it was received. I also sent one from Yahoo Mail - no error bounce however I cannot verify it was received.

The prior e-mail I sent to the MSN.COM address was March 8, 2025, February 18, 2025, January 27, 2025 and a bunch of times in 2024.

I don't know what changes Comcast or Microsoft might make to their mail servers which would allow a message on 3/8/2025 to be delivered and messages after 5/25/2025 to be rejected.

The MSN.COM domain is an alias (I think that's the right term) for OUTLOOK.COM as I understand things. Is it possible the alias has something to do with the DMARC error?

Would you like the additional Diagnostic information included in the bounce message?