Some outlook email accounts fail dkim but not others - NOT 365

Copper Contributor


Issue Outlook 2021 Desktop (and others)  One email account sending tests to mailgenius, or ANY other mail testing site yields dkim failure, dmarc failure.


Using the same outlook, on a different email address, even on the same domain name passes.  This ONLY happens in outlook, as I've tried all other mail clients such as webmail (from mail host using c-panel) phone, Thunderbird...they always pass 100% of the time.

.... further experimenting:  I found another client using Outlook 2010 on a different domain (different office completely) that also has the exact same issue of failing dkim,dmarc.  However, another user in the office on the same email domain using Outlook 2013 passes all tests.


I sent emails to Gmail to view the headers from a passing client and then the outlook account that fails tests (same email account with exact same settings and ports) it's like the entire dkim part is stripped out.  (I have the headers info and can post on difference checker if anyone is interested)


I've contacted my email host provider and they say the server side Dkim,dmarc signing does not discriminate and is static in it's behavior.


I've got 100 users using outlook of all different versions and have not tested further...I'm a bit afraid to find more...but at this rate I'm at 2% of outlook users having this issue.


It was suggested I post here.  I've been opening many tickets with my email host provider, and even at Spiceworks they are all stumped.


I'd love to cooperate in any way possible to find this issue.  I'm good at taking instructions from people that need data returned.  At this point, it's all I have to offer.


p.s. i even changed my email encoder to UTF-8 on office Outlook 2021 and no change in testing results.


this issue has given me a beat down twice over.

help me Obiwan Kenobi.


1 Reply




Hi Beau,


Thanks a lot for the time you shared with me today on our remote session, please find the below summary for our case:

  • MS support collected three samples for the quarantined emails from for analysis
  • I Analyzed the message header for few samples ( attached) and found the below :



       ; spf=pass (sender IP is smtp.mailfrom=email address removed for privacy reasons; dkim=fail (No key [DKIM DNS record not found]); dmarc=none action= header.from=email address removed for privacy reasons



                  v=1; a=rsa-sha256; c=relaxed/relaxed;; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Yz+xBG0EUYcMykZq9MM6krZkbxy35i9hCfQSgRZEtD4=;      



  • Checked the DKIM record for MSN on DKIM Inspector - dmarcian and found it is missing    (Query:
  • I Escalated the issue to PG team with high severity
  • We agreed to change the Sev to B.


Thanks and best regards.