Postfix: Gmail marking my email as spam

I'm been trying to understand why Gmail is treating the email sent from one of my domain/server as SPAM. I found a lot of threads here about this issue, however I checked the usual suspects like domain keys, spf etc.

My email is accepted by Outlook.com, which from my understanding has a lot more aggressive spam filter.

I tested my config using auth-results@verifier.port25.com and I got this:

SPF check:          pass
DomainKeys check:   neutral
DKIM check:         pass
Sender-ID check:    pass
SpamAssassin check: ham

Everything looks fine.

After sending an email to a gmail account I get this under the headers:

Received-SPF: pass (google.com: domain of user@mydomain.org designates 89.x.x.8 as permitted sender) client-ip=89.x.x.x;
Authentication-Results: mx.google.com;
       spf=pass (google.com: domain of user@mydomain.org designates 89.x.x.8 as permitted sender) smtp.mail=user@mydomain.org;
       dkim=pass header.i=@mydomain.org

As you can see, the email is passing on spf and dkim without issues on gmail servers.

Finally I checked my server IP, hostname and domain at http://mxtoolbox.com/blacklists.aspx for RBL blocks and they're not listed anywhere.

Why is gmail treating my emails as SPAM? It makes no sense, I've complied with every single good practice.

Other Note:

• Reverse DNS is also ok;


• Tests at http://www.allaboutspam.com are green except for Email server is not using BATV format;

Thank you.

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