I had the same experience with outlook.com and servers hosted by many cloud providers, including Linode.
The solution with Linode is very simple, just open a ticket and they'll get in touch with M$ and you'll be added into their whitelist. It usually takes 2 business days. Just make sure to have proper/valid SPF records and rDNS. On Mon, 6 Dec 2021 20:42:11 +0100 Daniele Nicolodi via mailop <mailop@mailop.org> wrote: > Hello, > > is outlook.com blocking all Linode IPv4 space or am I just unlucky? > > > eur.olc.protection.outlook.com[104.47.18.225] said: 550 5.7.1 > > Unfortunately, messages from [109.74.203.128] weren't sent. Please > > contact > > your Internet service provider since part of their network is on our > > block > > list (S3140). You can also refer your provider to > > http://mail.live.com/mail/troubleshooting.aspx#errors. > > [VI1EUR06FT017.eop-eur06.prod.protection.outlook.com] (in reply to MAIL > > FROM command) > > What is a good neighborhood to park a mail server these days? > > Cheers, > Dan > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop