SOLVED Remote mail exchanger SMTP-error (550)

[mortenmathiasen]

A new cpanel client having domain clientdomain.dk already uses gmail. To continue using gmail the domains mail exchanger is set to 'Remote mail exchanger' within cpanel. All fine, but it introduces an error when sending mails from within cpanel webmail:

SMTP-error (550): Could not add recipient "[email protected]" (The mail server could not deliver mail to [email protected]. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.)

I have checked the exim log regarding this:

exigrep [email protected] /var/log/exim_mainlog

2021-07-15 03:23:05 H=(webhost1.hostingdomain.dk) [::1]:42614 F=<[email protected]> A=dovecot_login:[email protected] rejected RCPT <[email protected]>: The mail server could not deliver mail to [email protected].  The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.

Anyone having an idea on how to solve this problem?

 

[cPRex]

Hey there! Is the domain's MX record also pointed to Gmail? If not, the DNS would still route that back to the local system.

 

[mortenmathiasen]

Yes, the MX records point to Gmail:

clientdomain.dk.     14400   IN      MX      1 aspmx.l.google.com.
clientdomain.dk.     14400   IN      MX      5 alt2.aspmx.l.google.com.
clientdomain.dk.     14400   IN      MX      5 alt1.aspmx.l.google.com.
clientdomain.dk.     14400   IN      MX      10 aspmx2.googlemail.com.
clientdomain.dk.     14400   IN      MX      10 aspmx3.googlemail.com.
clientdomain.dk.     14400   IN      MX      20 clientdomain.dk.

These records work just fine outside cPanel.

Inside cPanel Exim reports this error:

fail_remote_domains:
  driver = redirect
  domains = ! +local_domains : ! localhost : ! localhost.localdomain
  allow_fail
  data = ${if eq {$verify_mode}{S} \
        {:fail: The mail server does not recognize $local_part@$domain as a valid sender.} \
        {:fail: The mail server could not deliver mail to $local_part@$domain.  The account or domain may not exist, they may be blacklisted, or missing \
the proper dns entries.} \
  }

From this it seems that any remote domain will fail upon standard Exim setup?

 

[cPRex]

I'd recommend checking two things. The first, would be a "dig mx clientdomain.dk" from the cPanel server's command line, just so you can confirm your local server is reading those MX records properly.

The second thing would be to check the cPanel >> Track Delivery tool to see if that shows any odd routing.

 

[mortenmathiasen]

SOLVED!
The MX records were not available to Exim. After setting up a DNS-forwarder pointing to cPanels DNS everything works great.

[root@hostingdomain ~]# dig clientdomain.dk MX +short
5 alt1.aspmx.l.google.com.
10 aspmx3.googlemail.com.
5 alt2.aspmx.l.google.com.
1 aspmx.l.google.com.
10 aspmx2.googlemail.com.

Thanks a lot!

 

[cPRex]

I'm glad I could help get things on the right track!!