I am running a Debian 8 VPS for a couple of months now. I running several services, including a mailserver with Postfix and Dovecot. As far as I can tell, I have everything set up correctly. My IP is not blacklisted anywhere, the reputation is neutral. SPF, DKIM and DMARC are set up and working correctly. I am using TLS with a valid SSL certificate. I have set up an FQDN.
Tests like checktls, allaboutspam, mxtoolbox or mail-tester.com all return 0-1% spam probability and a 10/10 score.
Here are the Headers of mail sent by Thunderbird and the Owncloud webmailer:
Thunderbird: https://owncloud.fuchstim.de/s/TfLDXAFouQ9u7OW
Owncloud Webmailer: https://owncloud.fuchstim.de/s/hfd2euVbB6MjPZx
As you can see, SPF, DKIM and DMARC checks are passing. The mails are being marked as spam by Outlook / Hotmail as well.
What am I doing wrong?
If you need more detailed information about the configuration, please tell me (^^)
Based on the information provided and the fact that you do have a valid
PTRrecord, the only thing you seem to be missing is experience.For most lists, having a neutral reputation does not mean much when the volume analyzed is too low to draw conclusions. Sending more and more clean messages to different domains will progressively improve your inbox delivery rate.
Whilst clean mailing lists can help to build reputation, it can have a negative impact if anyone reports a message as spam (even by accident), and could also be badly perceived by a server that receives the same message content more than once. This last point can be improved by specifying mailing list headers (such as
list-Idandlist-unsubscribe).