I have a dedicated server running CentOS7 with Postfix, the problem is that all the sent mails are flagged as SPAM by hotmail and gmail despite DKIM, SPF, DomainKeys, DMARC records and keys wich are all OK (See photo1)headers from gmail

I'm using cloudflare in order to add the DMARC record, cause 1&1 dosen't allow it. I also checked PTR, and NS records, on mail-tester.com i get 10/10 with is great, on port25.com i get:

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

Please don't mark the question as duplicate, there is no similar case, my server IP is not blacklisted, i don't and never use/d email marketing, i own this IP from 1 year ago.

Thank you all in advance, Eugen P.

  • Try to contact the Hotmail/Outlook team, I've had the same issues and the only way I've been able to solve this is to get ahold of someone there. Dec 10, 2015 at 15:39
  • Hi, 80% of our clients are using gmail, is there a way to contact gmail support team? Dec 12, 2015 at 10:28
  • 1
    I believe GMail is more verbose about mail rejection and you should look at the mail's headers for why it gets marked as spam> Dec 12, 2015 at 17:01
  • It's worth noting that these email authentication entries don't affect whether the email goes to spam or not as far as I know. For example, an SPF hard fail tells the receiving machine to reject the email altogether but it's more of a suggestion subject to things like the policy set down by DMARC. But I'd test other variables against this and against the null hypothesis to see what happens. For example, remove all email auth temporarily, does that make any diff? Feb 22, 2017 at 17:14
  • Oops, I really need to look at the dates on questions as this isn't the first time I've tried to answer something that's a year or two old. Sorry. Feb 22, 2017 at 17:15

1 Answer 1


If anyone finds this post your answer could be to join: https://postmaster.live.com

hotmail.com; outlook.com and all the Microsoft services are reputation based. If you have a new mailserver that doesn't send much email to microsofts servers then you'll unlikely have a reputation. Join their postmaster website and list your IP's and then you can apply to have your reputation lifted.

This worked for me.

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