I have been following this tutorial: "The Perfect Server – Debian Lenny (Debian 5.0) With BIND & Dovecot [ISPConfig 3]"
Everything works fine except when I try to send mails to a hotmail account. I get this fault repport: (I use of course postfix)
This is the mail system at host server1.xxxxxxxxx.dk.
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
<email@example.com>: host mx4.hotmail.com[220.127.116.11] said: 550 SC-001
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. You can also refer your provider to
. (in reply to MAIL
I understand that it is something with Id-sender, but nothing more but that. Does somebody knows what i have to do?