My friend on CenturyLink, is trying to send me email, and suddenly she is unable to send email to me - never makes it to my Comcast inbox.

I'm having the same issue.  I haven't changed anything, and my friend hasn't changed anything, but all of a sudden his emails from q.com (a centurylink company) are not coming through.  He is getting that DMARC message as well.

Hello @user_eej9m8, Thanks so much for taking a moment out of your day to leave a comment on our community forum and we would be happy to help. Please check out these links to see if that helps:

Add Email Addresses to Your Email Safe List in Xfinity Email
When friends get error messages from your Comcast email

@XfinityShawn​ Yes, when she tries to send me an email to Comcast, from  her CenturyLink end, an image of a red traffic light appears, that says:  "Message blocked Your message to _____@comcast.net  [aka my comcast email address] has been blocked. See technical details below for more information." Then there's a link below that with "Learn More" and "This link will take you to a third-party site" and the hyperlink leads the Centurylink customer (my friend) to the below explanation in bold print.  However, we don't know what they are talking about, and are unable to correct the problem.  Since Comcast is blocking her messages from CenturyLink to me, CAN YOU UNBLOCK THEM, or fix it somehow.?? I have not heard of a resolution suggestion.  Thank you

 DM000001 :: Mail to Comcast is rejected and is returned with an error message containing the code DM000001. 

When we look up the error DM000001, this is the result we are finding. This message has been rejected by the Comcast mail servers due to the sending domain's published DMARC policy. The sending domain has published a DMARC reject policy, and this message has not passed either DKIM or SPF authentication for the domain. 

You may also want to speak to our Customer Security Assurance Team which you can find here - https://spa.xfinity.com/help/postmaster?faq=comcast-mail-errors

@Hillmac

Thanks for sharing those details — it definitely sounds like the issue is related to how your friend’s email is being processed through their provider’s servers. The error message points to a DMARC policy failure, which means Comcast is rejecting the email because it doesn’t meet certain authentication standards.

Since this involves email security protocols, the best next step is to reach out directly to our Customer Security Assurance (CSA) team. They specialize in handling situations like this and can investigate the rejection further.

You can get started here:

https://spa.xfinity.com/help/postmaster?faq=avoid-blocks-ipv4

That page includes information on how to avoid blocks and how to contact our security team if they believe the message is being incorrectly filtered. Let us know if you have any trouble connecting with them — we're here to help however we can.

Hi there, @user_cumwfh I'm very sorry for the trouble you are experiencing with not getting the emails that your friend is sending you. Have you reached out to our Customer Security Assurance team regarding this issue?-Richard

Yes, have reached out to the Customer Security Assurance team days ago, but did not see any specific reply.  Its as if the official employees don't really exist and its all just A I. Anyway, there has been a new development.  My friend with CenturyLink email was a composing an email on her computer at home, and suddenly everything blew up.  Flashing screen colors, loud noises and instructions to call the "Microsoft" phone number on the screen for more "assistance." Fortunately did not do that, and called her own legitimate IT company who helped resolve it remotely.  The IT person spotted a big virus or malware in her email stuff, and got rid of it. Afterward, she sent a test email from her CenturyLink q.com account to me at Comcast, and it successfully made it over to my email, not blocked.  So, I guess it is resolved, fingers crossed.  Perhaps that error code she kept seeing meant Comcast detected a virus from Century Link and would not let it through.  ?  Even though Richard is probably AI, I am sending this for others in the forum to see. Thanks!