550 Sender verify failed

Stefann

I have a problem, some email servers dont accept my emails.

stefan@delfzijlrp.nl: host mail.delfzijlrp.nl[185.114.156.185] said:
550-Verification failed for stefantjemail@stefanvt.nl 550 Sender verify
failed (in reply to RCPT TO command)

That is what i get when i sent an email to another webserver.
And when i send to hotmail i get a email back that a part of the providers network is on a blacklist.
When i send to gmail, the email will get into the spam folder.
I checked aswell as my network provider and we cant find that this ip or subnet is blacklisted.

If i go to DNS configuration in the https://mail.stefanvt.nl/ interface and check them, everything comes back fine.

My mailserver ip is: 5.181.134.46

Im hosting this on my own server that runs in a datacentre.

Maybe someone can help me with this.

kicou

Hi,

Try to send a mail to thoses testing mails servers, and look what’s wrong in the reports.
If the IP is blacklisted, should use a relay SMPT or manage to be unlisted (hard work).
How many mails to manage to send a day ?

https://www.mail-tester.com/
https://www.mailgenius.com/

Cedric

Stefann

kicou ive done this many times always receive a 10/10 on mail-tester.com

kicou

See, try mailgenius also, just in case.
No more idea !

Try a SMTP relay like sendinblue, free for 300 mails a day.
Should be ok directly after creating the sendinblue account, but your can add your domain for DKIM etc.
Just to see if that’s solve or not the problem (easy with mailcow UI to manage smtp relay)

Cedric

Stefann

kicou My results are 98. The only thing is that my domain is 4 days old, and i dont have a List-Unsubscribe header. that cant be the reason for this right ?

kicou

For list-unsubscribe no, should not ! I also don’t have it.
But for 4 days old domain, could be, depend of spam filter the remote server apply !

To test, try the sendinblue relay, it will use they own DKIM and domain for the relay out the box (don’t personnalize it).