Error 450 4.7.1 Client host rejected: cannot find your hostname, but PTR record is OK.

andre_onway

Registered
Nov 4, 2019
1
0
1
Brasil
cPanel Access Level
Root Administrator
Hello people.

I'm new to cPanel / WHM but specializing in Linux and servers.

I have 4 IP addresses for my server.

I needed to make the IP change for one domain only (eg: server01.cwbsistemas.com.br), the others remain with the same IP.

I managed to make change by the WHM panel, but now the emails are coming back with the error:

host fagundez.domain.com.br [<IP REMOVED>]
SMTP error from remote mail server after RCPT TO: <[email protected]>:
450 4.7.1 Client host rejected: cannot find your hostname, [<IP REMOVED>]:
retry timeout exceeded

I checked several solutions and the PTR is correct.

And the exim settings too.

Does anyone have any ideas ?

Forgive my English is from automatic translation.
 
Last edited by a moderator:

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,296
1,271
313
Houston
Hello,

This is typically a symptom of cached rDNS lookups - which would make a lot of sense if you'd just changed the IP address or you've manually entered the host into /etc/mailhelo