https://olcsupport.office.com/
Hi,
ip 147.78.184.50/32 has been assigned to one new mail server in our infrastructure, when our customers try to send an email to hotmail.com/hotmail.it/live.com/etc recipients this error retuns:
<vdsarredamento@outlook.it>: host eur.olc.protection.outlook.com[104.47.17.161]
said: 550 5.7.1 Unfortunately, messages from [147.78.184.50] 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
http://mail.live.com/mail/troubleshooting.aspx#errors.
[VI1EUR05FT056.eop-eur05.prod.protection.outlook.com
2023-04-03T09:54:15.595Z 08DB33EC8E0E9D76] (in reply to MAIL FROM command)