When sending letters to the outlook.com domain from our mail server, the letters are blocked, how to get out of the situation?

Question

postfix

Good afternoon. I have my own Feng Shui configured mail server (with dkim, etc.). We have a lot of users working with outlook mail (and hotmail, as I understand it now is the same thing). When sending them emails from our mail server, a letter is returned with the following content: 550 5.7.1 Unfortunately, messages from [Our IP] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to mail.live.com/mail/troubleshooting.aspx#errors . [AM5EUR02FT062.eop-EUR02.prod.protection.outlook.com] (in reply to MAIL FROM command)).

I signed up for their Smart Network Data Services program to no avail. sent the answer that: We have completed reviewing the IP(s) you submitted. The following table contains the results of our investigation.
Not qualified for mitigation
Our investigation has determined that the above IP(s) do not qualify for mitigation.

Has anyone come across them? how do i get on their whitelist? Thank you in advance

Answer 1

And you reply with a letter. I answered, in a couple of days a live person unblocked me without questions