Your message appears to be sent from

Hello ,

I have the latest Cyber Panel installation with 3 domains installed.
When I am sending emails from all 3 domains sometimes I get back the error:

This is the mail system at host

I’m sorry to have to inform you that your message could not be delivered to one or more recipients. It’s attached below.[2a00:1450:400c:c1b::1a]
said: 550-5.7.1 [2a02:c206:2065:3328::1] Our system has detected that this
message 550-5.7.1 does not meet IPv6 sending guidelines regarding PTR
records and 550-5.7.1 authentication. Please review 550-5.7.1
Prevent mail to Gmail users from being blocked or sent to spam - Gmail Help for more information 550
5.7.1 . f1-20020a5d64c1000000b0023186ac97bbsi13071756wri.24 - gsmtp (in
reply to end of DATA command)

And the email was not send.

When I make a test at to see the score I’ve got, the result is¨

You’re not fully authenticated

Your IP address is associated with the domain vps.****.gr .
Nevertheless your message appears to be sent from mail.**********.tours .

I already setup my Reverse DNS at my contabo VPS server both Ipv4 and v6 the hostname of my server.
But I have NO idea why my e-mail messages appearing to be send from one of my 3 domains mail.*****.tours where is this option ? I cannot find it anywhere!



where dns managed?

I am using cloudflare name servers as always.
Also I am not using rainloop, I setup my email at Microsoft outlook. But even if I send email from Rainloop i have the same error

The error was at postfix helo configuration!

Here are the tested values for this check:

  • IP:
  • HELO: vps.******.gr
  • rDNS: vps.*****.gr

when changed all is working great

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