Hello, I setup a mail server using a Ubuntu CyberPanel droplet, everything is properly configured. Test results are 10/10, link here: https://www.mail-tester.com/test-8egaldi6p
The following message was received from outlook:
This is the mail system at host domain.com.
I’m sorry to have to inform you that your message could not be delivered to one or more recipients. It’s attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can delete your own text from the attached returned message.
The mail system
firstname.lastname@example.org: host outlook-com.olc.protection.outlook.com[220.127.116.11] said: 550 5.7.1 Unfortunately, messages from [18.104.22.168] 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. [MW2NAM12FT006.eop-nam12.prod.protection.outlook.com] (in reply to MAIL FROM command)
This textbox defaults to using Markdown to format your answer.
You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!
These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.
Join our DigitalOcean community of over a million developers for free! Get help and share knowledge in Q&A, subscribe to topics of interest, and get courses and tools that will help you grow as a developer and scale your project or business.
Click below to sign up and get $100 of credit to try our products over 60 days!