And y'all thought the MS mitigation process couldn't get more circuitous... based on my experience today, the new process is:
1) Get notified that your IP(s) is on the MS 'block list'. Fill out the form. 2) Get a response saying nothing was found, or not eligible for mitigation. 3) Reply (except you can't JUST reply, you must edit the To address as instructed in their response) requesting review. 4) Receive a reply asking you to (redundantly) provide Exact sending IP address : Exact Sending domain: Complete Error message with time stamp: Explain the issue in detail: 5) Wait for "issue mitigated" response. So far, I've gotten one "mitigated" reply; waiting on two others. I'm pretty sure this is all contracted out to low-paid, low-skilled workers in India. On Wed, May 6, 2026 at 7:07 PM Dave Dewey via mailop <[email protected]> wrote: > Yes, as of last night. Again. > Same as last time (January?) - SNDS reporting clean and green, no issues, > Microsoft says there is no block on my IP. > Hopefully the same remedy works as last time - open a ticket, get an > automated response that there’s nothing to fix, respond again with > logs/data and hope to get a human response who can fix it. > > Fill out a ticket here, unless you have some other support channel (sounds > like you might): > https://olcsupport.office.com/ > > On May 6, 2026, at 5:49 PM, Areeb via mailop <[email protected]> wrote: > > Hi all, > > Is anyone else running into Microsoft blocks (S3150, Ratelimiting) at the > moment? We’ve suddenly started seeing entire IP range blocks across two of > our ranges, including customers using dedicated IPs. > > Microsoft support has been particularly unhelpful. Nothing abnormal in our > logs. > > [image: Regards,] > Areeb Majeed > Co-founder, > Maileroo > > [image: icon] maileroo.com [image: icon] [email protected] > > [image: facebook] <https://facebook.com/maileroo> > > [image: linkedin] <https://www.linkedin.com/company/maileroo/> > > [image: twitter] <https://twitter.com/maileroodotcom> > > [image: __tpx__] > *Maileroo Group Pty Ltd |* Level 10, 440 Collins Street, Melbourne VIC > 3000 > > On 6/05/2026 11:49:38 PM, [email protected] < > [email protected]> wrote: > Send mailop mailing list submissions to > [email protected] > > 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 > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of mailop digest..." > > > Today's Topics: > > 1. Re: mailop Digest, Vol 70, Issue 8 (Thomas Walter) > 2. Re: Suspect DKIM failure to Microsoft destination > (Jonathan Loriaux) > 3. Re: Suspect DKIM failure to Microsoft destination (Paulo Azevedo) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 6 May 2026 12:56:00 +0200 > From: Thomas Walter > To: [email protected] > Subject: Re: [mailop] mailop Digest, Vol 70, Issue 8 > Message-ID: > Content-Type: text/plain; charset="utf-8" > > Thanks Areeb, > > On 06.05.26 11:34, Areeb via mailop wrote: > > Having the same issue, they are sending the email through a no reply > > email address. You need to change the address in the To field > > from [email protected] > > to [email protected]. > > This just confirmed, I'm stupid. The original mail from Microsoft tells > me in red > > ----- > *This is an automated message from an unmonitored mailbox. To ensure > your reply reaches us, please include > [email protected] in the “To” field when responding. > ----- > > But of course if you are in a hurry, you don't read the red important > letters and just hit reply, because you know you have to escalate the > ticket anyway. > > Regards, > Thomas Walter > > -- > Thomas Walter > Datenverarbeitungszentrale > > FH Münster > - University of Applied Sciences - > Corrensstr. 25, Raum B 112 > 48149 Münster > > Tel: +49 251 83 64 908 > Fax: +49 251 83 64 910 > www.fh-muenster.de/dvz/ > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: smime.p7s > Type: application/pkcs7-signature > Size: 4819 bytes > Desc: S/MIME Cryptographic Signature > URL: > > ------------------------------ > > Message: 2 > Date: Wed, 6 May 2026 09:17:00 +0200 > From: Jonathan Loriaux > To: [email protected] > Subject: Re: [mailop] Suspect DKIM failure to Microsoft destination > Message-ID: <[email protected]> > Content-Type: text/plain; charset="utf-8"; Format="flowed" > > Hi David, > > To properly identify the problem, you need to analyze the SMTP headers > of a successfully delivered email (to a different destination, for > example). > > Feel free to contact me privately if you need help. > > Jonathan > > P.s. : N'hésitez pas à vous inscrire à nos newsletters : > https://www.badsender.com/newsletter/inscription/ > > > *-- > Jonathan Loriaux* > > CRM Consultant and > Co-director of Badsender > > > > 07.62.33.33.47 > > [email protected] > > badsender.com > > lepatron.email > > Facebook Twitter > Linkedin > > > Book a meeting with me > > > > > > On 5/6/26 08:57, Hello Maildrop via mailop wrote: > > Hello, > > > > One of my customer, hosted at Google workspace, have recurrent problem > > when sending to some addresses at live.fr or > > hotmail.com > > > > The messages bounce back indicating a DKIM failure, however the > > messages sended are well signed. Delivery to other destinations > > enforcing DKIM/DMARC does not cause any problems (Gmail, Orange) > > > > 550 5.7.515 Access denied, sending domain MISSEGLE.COM > > 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 > > [AM8P189MB1234.EURP189.PROD.OUTLOOK.COM > > > > 2026-05-06T05:21:48.296Z 08DEAAD6427386FD] > > [DU2PR04CA0024.eurprd04.prod.outlook.com > > > > 2026-05-06T05:21:48.305Z 08DEAAEBE699717D] > > [DB1PEPF000509FE.eurprd03.prod.outlook.com > > > > 2026-05-06T05:21:48.308Z 08DEA716CB8BDD0A] > > > > I can't identify the cause of this problem, do you have any ideas? > > > > *TOUREL David* > > > > *MAILDROP* > > 17 ch de la Longuié - 81210 MONTFA > > > > Tél : 05 63 51 07 79 > > > > Retrouvez-nous sur Twitter @maildrop_fr > > > > _______________________________________________ > > mailop mailing list > > [email protected] > > https://list.mailop.org/listinfo/mailop > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > > ------------------------------ > > Message: 3 > Date: Wed, 6 May 2026 14:40:12 +0100 > From: Paulo Azevedo > To: [email protected] > Subject: Re: [mailop] Suspect DKIM failure to Microsoft destination > Message-ID: > > Content-Type: text/plain; charset="utf-8" > > Hi all. > > I had a similar issue with a customer: turned out that the "script" > generating the email message wasn't adding a Message-ID header. > Had the server add the missing header before dkim signing, issue solved. > > Sometimes the devil is on the details ... > > > On Wed, May 6, 2026 at 12:26 PM Jonathan Loriaux via mailop < > [email protected]> wrote: > > > Hi David, > > > > To properly identify the problem, you need to analyze the SMTP headers > of > > a successfully delivered email (to a different destination, for > example). > > > > Feel free to contact me privately if you need help. > > > > Jonathan > > P.s. : N'hésitez pas à vous inscrire à nos newsletters : > > https://www.badsender.com/newsletter/inscription/ > > > > > > *-- Jonathan Loriaux* > > > > CRM Consultant and > > Co-director of Badsender > > > > 07.62.33.33.47 <+33762333347> > > > > [email protected] > > > > badsender.com > > > > lepatron.email > > > > Facebook Twitter > > Linkedin > > > > > > Book a meeting with me > > > > > > > > > > On 5/6/26 08:57, Hello Maildrop via mailop wrote: > > > > Hello, > > > > One of my customer, hosted at Google workspace, have recurrent problem > > when sending to some addresses at live.fr or hotmail.com > > > > The messages bounce back indicating a DKIM failure, however the messages > > sended are well signed. Delivery to other destinations enforcing > DKIM/DMARC > > does not cause any problems (Gmail, Orange) > > > > 550 5.7.515 Access denied, sending domain MISSEGLE.COM 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 [AM8P189MB1234.EURP189.PROD.OUTLOOK.COM > > 2026-05-06T05:21:48.296Z 08DEAAD6427386FD] [ > > DU2PR04CA0024.eurprd04.prod.outlook.com 2026-05-06T05:21:48.305Z > > 08DEAAEBE699717D] [DB1PEPF000509FE.eurprd03.prod.outlook.com > > 2026-05-06T05:21:48.308Z 08DEA716CB8BDD0A] > > > > I can't identify the cause of this problem, do you have any ideas? > > > > *TOUREL David* > > > > *MAILDROP* > > 17 ch de la Longuié - 81210 MONTFA > > > > Tél : 05 63 51 07 79 > > Retrouvez-nous sur Twitter @maildrop_fr > > > > _______________________________________________ > > mailop mailing [email protected]:// > list.mailop.org/listinfo/mailop > > > > _______________________________________________ > > mailop mailing list > > [email protected] > > https://list.mailop.org/listinfo/mailop > > > > > -- > -- > Paulo Azevedo > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop > > > ------------------------------ > > End of mailop Digest, Vol 70, Issue 10 > ************************************** > > [image: 1ad70c48-09eb-4e91-9119-91fe238fce5b] > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop > > > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop >
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