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Topic: Emails to Gmail/Outlook Keep Getting Rejected or Marked as Spam – Need

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.7.4
- Deployed with iRedMail Easy or the downloadable installer? Yes
- Linux/BSD distribution name and version: Ubuntu 22.04 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): (Backend: mariadb)
- Web server (Apache or Nginx):NginX
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
Hi all,

I’m running into a really frustrating issue and I hope someone here can give me some advice.

Whenever I send emails from my iRedMail server to big providers like Gmail or Outlook/Hotmail, the messages often either:

Get rejected with errors like 550 5.7.1 – Message not accepted due to spam/DMARC policies, or

End up in the Spam/Junk folder, even though I’ve already set up SPF, DKIM, and DMARC correctly.

Microsoft seems to be especially strict — even with a fresh server and clean IP, I still get delivery problems.

Is there anything extra I should configure in DNS (aside from SPF/DKIM/DMARC and rDNS)?

I’ve spent a lot of time tweaking configs, but the results are still inconsistent. Any practical tips or personal experiences would be really appreciated.

Thanks in advance!

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Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 (edited by Cthulhu 2025-10-02 09:01:36)

Re: Emails to Gmail/Outlook Keep Getting Rejected or Marked as Spam – Need

You should try those:

1) https://sendersupport.olc.protection.ou … leshooting

2) https://gmail.com/postmaster/

Make sure that all your SPF, PTR, DMARC policies are correct, and that your IP is not on a blacklisted subnetwork