I setup a mail server on mail.mydomain.com. I am able to receive email. Problem occurs when i try to send an email. I have two servers:

  • mail.mydomain.com - which is on different ip (e.g.
  • mydomain.com - which has also different ip (

My SPF record says: v=spf1 mx ip4: -all

My mx record for mydomain.com points to mail.mydomain.com

When i try to send an email I'm getting following error:

From google:

gmail-smtp-in.l.google.com[2a00:1450:400c:c06::1b] said: 550-5.7.1 [2001:bc8:4400:2b00::32:1f 12] Our system has detected that this 550-5.7.1 message is likely unsolicited mail. To reduce the amount of spam sent 550-5.7.1 to Gmail, this message has been blocked. Please visit 550-5.7.1 https://support.google.com/mail/?p=UnsolicitedMessageError 550 5.7.1 for more information. m21si1136366wml.110 - gsmtp (in reply to end of DATA command)

From other server:

host mx1.seznam.cz[2a02:598:2::42] said: 550 5.7.1 Sender Policy Framework of `futeq.com' domain denied your IP address. (in reply to MAIL FROM command)

For gmail I also registered and verified my domain using postmaster.google.com

Can anyone point me to the right direction? am I missing something ?

PS: I checked and my IP is not blacklisted


  • 1
    The addresses in both log entries show an IPv6 address, not the IPv4 address in your SPF record. You need to add the IPv6 entry if the system will be using IPv6 to send email as well.
    – user143703
    Mar 2, 2019 at 23:12
  • thank you. does that mean I'll have to have 2 SPF entries ? Mar 2, 2019 at 23:15

1 Answer 1


It looks like you forgot to add your IPv6 address to your SPF record, and quite possibly to your DNS AAAA record for the sending host.

Of course, mx in the SPF record covers all IP addresses of the host named in the MX record, so naming the same IP addresses in the SPF record is redundant.

To fix the problem, add your IPv6 address in the DNS AAAA record for your host.

  • thank you, now I only need to deal with almost everyone marking me as spam (except gmail :) )any tips ? Mar 3, 2019 at 0:42
  • @BranislavB. proper reverse DNS (should match whatever you use in your HELO) and a configured SSL certificate with the same name works for me. also check your names and IPs against known blacklists and see what you can do about removal
    – ivanivan
    Mar 3, 2019 at 1:15

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .