Resolved Mailserver says 450 - unverified adress

[speedbird]

Hello there,
I've got a problem with an email I just can't get sent to an address because the mail system of the receiver answers with this:

mail postfix/smtp[29969]: E5DCF60327: to=<***@***.de>, relay=mail.***.de[***]:25, delay=5022, delays=5021/0.01/0.2/0.12, dsn=4.1.7, status=deferred (host mail.***.de[***] said: 450 4.1.7 <**@***>: Sender address rejected: unverified address: The sender address of your mail could not be verified as existing (in reply to RCPT TO command))

It only happens with this particular recipient and I've not seen this anywhere else so far.

My rDNS record is set correctly to mail.mydomain.tld
In my DNS settings there is the record for mail.mydomain.tld
The address I'm sending from does exist.
Postfix Config as mydomain and myhostname set to mail.mydomain.tld
Postgrey is running on this system but does no difference if disabled
SPF and DKIM is disabled

How come it says the address could not be verified?

Thanks a lot!

 

[Bence Bokor]

Hi,

I am suggesting to use SPF and DKIM. Not sure, but it could be a relay problem.

You could add your mail.***.de domain as verified mail sender.

E.g.
v=spf1 a mx a:mail.****.de ~all

 

[speedbird]

It suddenly just went through after being in the queue for almost a day. Don't know why. Server tried it again and suddenly got a status 250 back. Checked on my contact and it actually was delivered to his inbox.