<div dir="ltr"><div>Okay, just resolved this from my end. My O365 emails were being DKIM signed but by our .<a href="http://onmicrosoft.com">onmicrosoft.com</a> subdomain instead of the actual sending domain. Headers would show dkim=pass but the DKIM domain didn't match the FROM address in our envelopes.<br></div><div><br></div><div>Had to enable DKIM signing on the custom domain in O365 here <a href="https://security.microsoft.com/authentication?viewid=DKIM">https://security.microsoft.com/authentication?viewid=DKIM</a> and setup CNAMEs for the proper selectors in DNS.</div><div><br></div><div>DMARC reports from Yahoo helped me a ton here, but they were confusing. They showed DKIM failed in the policy_evaulated -> disposition section but showed result = pass in the auth_results -> dkim section.</div><div><br></div><div>Just had my first successful email to Yahoo.com in days. Looks like the O365 DNSRBL inclusion was a red herring.<br></div><div><br></div><div>- Cary<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Mar 11, 2024 at 1:34 PM Cary Wiedemann <<a href="mailto:carywiedemann@gmail.com">carywiedemann@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Massive problems with email delivery to Yahoo and AOL today, they share a mail system on the back-end. Microsoft issued advisory EX719348<span><span dir="ltr"> last Thursday for their IPs being included in some DNSRBLs, and I still see some of their IPs on the Spamhaus RBL </span></span>(40.107.102.127) but I'm not sure if that's the root cause.</div><div><br></div><div>All my emails from O365 to Yahoo and AOL have been failing since 3/7.</div><div><br></div><div>Lots of noise and confusion because Yahoo and AOL recently started enforcing stricter SPF/DKIM/DMARC requirements, but this seems to be unrelated. These emails are DKIM signed, pass SPF, and have a valid DMARC record.<br></div><div><br></div><div>Still investigating, will update the list with the eventual resolution.</div><div><br></div><div>- Cary<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Mar 11, 2024 at 1:27 PM bannereddivpool via Outages <<a href="mailto:outages@outages.org" target="_blank">outages@outages.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr">Anyone seeing any issues with yahoo email services? I keep getting dropped;<div><br></div><div><div>telnet <a href="http://mta6.am0.yahoodns.net" target="_blank">mta6.am0.yahoodns.net</a> 25</div><div>Trying 67.195.204.74...</div><div>Connected to <a href="http://mta6.am0.yahoodns.net" target="_blank">mta6.am0.yahoodns.net</a>.</div><div>Escape character is '^]'.</div><div>220 <a href="http://mtaproxy501.free.mail.bf1.yahoo.com" target="_blank">mtaproxy501.free.mail.bf1.yahoo.com</a> ESMTP ready</div><div>EHLO <a href="http://mail.yahoo.com" target="_blank">mail.yahoo.com</a></div><div><a href="http://250-mtaproxy501.free.mail.bf1.yahoo.com" target="_blank">250-mtaproxy501.free.mail.bf1.yahoo.com</a></div><div>250-PIPELINING</div><div>250-SIZE 41943040</div><div>250-8BITMIME</div><div>250 STARTTLS</div><div>Connection closed by foreign host.</div></div><div><br></div><div>Sending from outlook and I'm getting this as well;</div><div><br></div><div><p><b><span style="font-size:10pt;font-family:Tahoma,sans-serif;color:gray">Diagnostic
information for administrators:</span></b><span style="font-size:10pt;font-family:Tahoma,sans-serif;color:gray"><span></span></span></p>
<p><span style="font-size:10pt;font-family:Tahoma,sans-serif;color:gray">Generating
server: <a href="http://SJ2PR14MB6550.namprd14.prod.outlook.com" target="_blank">SJ2PR14MB6550.namprd14.prod.outlook.com</a><br>
Total retry attempts: 7<span></span></span></p>
<p><span style="font-size:10pt;font-family:Tahoma,sans-serif;color:gray"><a href="mailto:babyereed2013@yahoo.com" target="_blank">sample1@yahoo.com</a><br>
Remote server returned '550 5.4.300 Message expired -> 451 [RL01] Message
temporarily deferred'<span></span></span></p>
<p><span style="font-size:10pt;font-family:Tahoma,sans-serif;color:gray"><a href="mailto:jbliqemp@yahoo.com" target="_blank">sample2@yahoo.com</a><br>
Remote server returned '550 5.4.300 Message expired -> 451 [RL01] Message
temporarily deferred'<span></span></span></p>
<p><span style="font-size:10pt;font-family:Tahoma,sans-serif;color:gray">Original
message headers:<span></span></span></p></div></div></div></div>
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