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Hi, we have our email server on premise, with 2 ISPs (1 as the main link and 1 as the failover). Also, I had this problem on our main IP too, and fixed the issue following the same steps described below.
About a year ago we got a new failover IP and we're not able to send any emails to Microsoft through the new IP.
Many email providers don't seem to mind the new IP, including Google (gmail), but on my personal account (hotmail) I can't receive anything, just a bounce email saying
host said: 550 5.7.1
Unfortunately, messages from [X.X.X.X] weren't sent. Please contact your Internet service provider since their network is on our block list (S3150).
Upon further investigation (checking for the IP on https://mxtoolbox.com ), I found out that my IP was blacklisted for SPAM back on 2017, so I went through all the authorities requesting to drop us from their blacklists, and they did (confirmed by email and again checking on https://mxtoolbox.com).
The only piece that seems to be missing is to request Microsoft to delist us, but going to https://sender.office.com doesn't show any results, they just deny my requests without further explanation saying
The request to delist IP address X.X.X.X has been denied, and we have escalated your request to Microsoft Support.
DNS seems to be set correctly with SPF, DKIM and DMARC, and the ISP already set the PTR to point our domain to the failover IP, what am I missing? What should I do? I'm very confused.
Best,
Thales
PS: The tag on the question might be wrong, sorry about that
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Hi @Thales Cardoso ,
Please kindly understand that the Outlook tag here we mainly focus on general issues about build-in feature in Outlook desktop client and your issue is beyond our support. And it's suggested that you could try to contact support by Global Customer service Phone number for more help!
I figured that the tag was wrong, but I couldn't find any tag that related to my problem,
I'm hopping from forum to forum trying to fix my issue and I landed here, sorry about that.
I'll try to contact the Global Costumer Service, thank you for the help!
From a similar post found at https://answers.microsoft.com/en-us/outlook_com/forum/all/hotmailoutlook-blacklist-removal-form/86c71c17-80c9-48e9-b822-1d3678f19673
Try filling out the following form found at http://go.microsoft.com/fwlink/?linkid=614866 (Outlook.com Delivery Team support request)
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If this is helpful please accept answer.
I'll try it, thank you!
Try filling out the following form found at http://go.microsoft.com/fwlink/?linkid=614866 (Outlook.com Delivery Team support request)
Thank you @Dillon Silzer !!
I filled the form that you linked and they solved my problem!
After a little back and forth they managed to delist me, took 24 hours to propagate the configuration, but it's a win!
Again, sorry for the wrong tag/forum, there is not much help out there for this stuff, at least not that I could find.