Double-check your DMARC policy and ensure it has the RUA tag in place. Apparently, MSFT is requiring that (they do not honor having only a RUF, btw).
On Saturday, June 21st, 2025 at 06:00, mailop-requ...@mailop.org <mailop-requ...@mailop.org> wrote: > Send mailop mailing list submissions to > mailop@mailop.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://list.mailop.org/listinfo/mailop > or, via email, send a message with subject or body 'help' to > mailop-requ...@mailop.org > > You can reach the person managing the list at > mailop-ow...@mailop.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of mailop digest..." > > > Today's Topics: > > 1. DKIM failures from Microsoft (Mark Fletcher) > 2. Re: DKIM failures from Microsoft (Mark Alley) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 20 Jun 2025 13:36:49 -0700 > From: Mark Fletcher ma...@corp.groups.io > > To: mailop mailop@mailop.org > > Subject: [mailop] DKIM failures from Microsoft > Message-ID: > caeo096qaoueay4nacktha8dzobstu2peibzcfmeg3vdirqg...@mail.gmail.com > > Content-Type: text/plain; charset="utf-8" > > Hi All, > > We're seeing instances of emails being rejected by Microsoft with DKIM > errors, and I have no idea why. It's happening to maybe 1% of the email we > send to Microsoft properties (outlook.com, hotmail.com, live.com, etc). The > error we get is: > > 550 5.7.515 Access denied, sending domain GROUPS.IO doesn't meet the > required authentication level. The sender's domain in the 5322.From address > doesn't meet the authentication requirements defined for the sender. To > learn how to fix this see: https://go.microsoft.com/fwlink/p/?linkid=2319303 > Spf= Pass , Dkim= Fail , DMARC= Pass > > These are email group messages. We re-write the From line for all of them, > so they all have the @groups.io domain. For a given list message, if it > fails for one Microsoft recipient, it fails for all of them. > > I dump out these emails and run two different DKIM signature check > programs on them, and they pass. > > Does anyone have any suggestions for things I should check? > > Thanks, > Mark > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > https://list.mailop.org/private/mailop/attachments/20250620/b75feef9/attachment-0001.htm > > > ------------------------------ > > Message: 2 > Date: Fri, 20 Jun 2025 16:00:48 -0500 > From: Mark Alley mark.al...@tekmarc.com > > To: mailop@mailop.org > Subject: Re: [mailop] DKIM failures from Microsoft > Message-ID: 96ea7adf-afe6-4d87-b62d-cf0b19d0a...@tekmarc.com > > Content-Type: text/plain; charset="utf-8"; Format="flowed" > > It's the exact same problem as the other mailop thread "Outlook.com: > intermittent DKIM failures". > > It's not you, it's them. > > - Mark Alley > > On 6/20/2025 3:36 PM, Mark Fletcher via mailop wrote: > > > Hi All, > > > > We're seeing instances of emails being rejected by Microsoft with DKIM > > errors, and I have no idea why. It's happening to maybe 1% of the > > email we send to Microsoft properties (outlook.com > > http://outlook.com, hotmail.com http://hotmail.com, live.com > > http://live.com, etc). The error we get is: > > > > 550 5.7.515 Access denied, sending domain GROUPS.IO http://GROUPS.IO > > doesn't meet the required authentication level. The sender's domain in > > the 5322.From address doesn't meet the authentication requirements > > defined for the sender. To learn how to fix this see: > > https://go.microsoft.com/fwlink/p/?linkid=2319303 Spf= Pass , Dkim= > > Fail , DMARC= Pass > > > > These are email group messages. We re-write the From line for all of > > them, so they all have the @groups.io domain. For a given list > > message, if it fails for one Microsoft recipient, it fails for all of > > them. > > > > I dump out these emails and run two different DKIM signature check > > programs on them, and they pass. > > > > Does anyone have any suggestions for things I should check? > > > > Thanks, > > Mark > > > > _______________________________________________ > > mailop mailing list > > mailop@mailop.org > > https://list.mailop.org/listinfo/mailop > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > https://list.mailop.org/private/mailop/attachments/20250620/365a231f/attachment-0001.htm > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop > > > ------------------------------ > > End of mailop Digest, Vol 59, Issue 24 > **************************************
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