450 4.7.1 Client host rejected: cannot find your hostname

Operating System & Version
CentOS 7
cPanel & WHM Version
84.0.21

Inovacije doo

Member
May 11, 2013
9
0
1
cPanel Access Level
Root Administrator
Hello,

i need help regarding error while sending email to one of my clients. I'm getting this email in return:


Code:
SMTP error from remote mail server after RCPT TO:<[email protected]>: 450 4.7.1
Client host rejected: cannot find your hostname, [<IPADDRESS>]
Note: rDNS is set with main server IP 159.69.xxx.xxx, DMARC is set to email sending domain, exim is properly configured:
- Reference /etc/mailhelo for custom outgoing SMTP HELO (ON)
- Reference /etc/mailips for custom IP on outgoing SMTP connections (ON)

Any suggestions to change in some settings on my server or this is the problem on other server receiving email?

Thanks
 
Last edited by a moderator:

cPanelLauren

Forums Analyst II
Staff member
Nov 14, 2017
9,366
799
263
Houston
The issue here is that the system cannot resolve your hostname to an IP address. Your PTR record notes omega.domain-cloud.net (i replaced the actual domain name) as the hostname but when I perform a dig query for the A record for that domain it does not come back with any results:

Code:
[[email protected] ~]# dig a omega.domain-cloud.net +short
[[email protected] ~]#