Reboot the damn server:

service zimbra stop && reboot

Check Zimbra status:

service zimbra status

https://wiki.zimbra.com/wiki/Postfix-Queue-ID-vs.-message-id-MTA

When a message enters the Postfix system [incoming or outgoing] it is immediately assigned a queue ID. Postfix/ZCS will most likely have a message leave the postfix queue for other processing: amavis, filters, etc. This will cause the message to get a new queue ID(s). This can also happen if you were to requeue your messages by doing something like: postsuper -r. You will need to note the message-id and ALL queue ID's to get the complete picture of what was happening for a particular email.

Find the Message ID in the message headers, then use it to find the associated Queue IDs:

egrep "1544469627.145884.1473273227065.JavaMail.zimbra@virtualarchitects.com" /var/log/zimbra.log

egrep "1544469627.145884.1473273227065.JavaMail.zimbra@virtualarchitects.com|225D286F6F|3C18086F7A|B590286F6F" /var/log/zimbra.log

http://wiki.zextras.com/wiki/ZeXtras_Suite_and_the_Zimbra_DoSFilter

http://wiki.zimbra.com/wiki/DoSFilter

grep DoSFilter /opt/zimbra/log/mailbox.log

grep DoSFilter /opt/zimbra/log/zmmailboxd.out

Get current values:

su - zimbra
zmprov gcf zimbraHttpThrottleSafeIPs
zmprov gcf zimbraHttpDosFilterMaxRequestsPerSec
zmprov gcf zimbraHttpDosFilterDelayMillis

Set additional safe IPs:

zmprov mcf +zimbraHttpThrottleSafeIPs 192.168.0.65
zmprov mcf +zimbraHttpThrottleSafeIPs 192.168.0.66

zmmailboxdctl restart

Comment out the IPv6 line:

vim /etc/hosts

#::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Then:

systemctl start zimbra

It didn't seem to matter what I did with /etc/aliases.

http://wiki.zimbra.com/index.php?title=How_to_%22fix%22_system%27s_sendmail_to_use_that_of_zimbra

/usr/sbin/alternatives --install /usr/sbin/sendmail mta /opt/zimbra/postfix/sbin/sendmail 25 \
    --slave /usr/bin/mailq mta-mailq /opt/zimbra/postfix/sbin/mailq \
    --slave /usr/bin/newaliases mta-newaliases /opt/zimbra/postfix/sbin/newaliases \
    --slave /usr/share/man/man1/mailq.1.gz mta-mailqman /opt/zimbra/postfix/man/man1/mailq.1 \
    --slave /usr/share/man/man1/newaliases.1.gz mta-newaliasesman /opt/zimbra/postfix/man/man1/newaliases.1 \
    --slave /usr/share/man/man8/sendmail.8.gz mta-sendmailman /opt/zimbra/postfix/man/man1/sendmail.1 \
    --slave /usr/share/man/man5/aliases.5.gz mta-aliasesman /opt/zimbra/postfix/share/man/man5/aliases.5 \
    --initscript zimbra
/usr/sbin/alternatives --config mta

If mail sent to root does not flow into the admin mailbox, check:

tail -30 /var/log/maillog

You may see errors like:

Nov  5 10:06:29 zimbra postfix/smtp[7400]: BCAAD18289B: to=<root@zimbra.virtualarchitects.com>, relay=none, delay=0.06, delays=0.01/0.04/0/0, dsn=5.4.6, status=bounced (mail for zimbra.virtualarchitects.com loops back to myself)

You can also test like this:

echo foo | /usr/sbin/sendmail -f root root && tail -f /var/log/maillog

In our default Zimbra installation, we only had one domain virtualarchitects.com, but root's mail was aliased to “root@zimbra.virtualarchitects.com”. So I added an alias domain “zimbra.virtualarchitects.com” and an additional mail alias to admin of “root@zimbra.virtualarchitects.com”:

su - zimbra
zmprov createAliasDomain zimbra.virtualarchitects.com virtualarchitects.com
zmprov aaa admin@virtualarchitects.com root@zimbra.virtualarchitects.com

Consider using firewall port forwarding (i.e 2222 → 22) instead of changing the SSH server on the Zimbra server.

If you changed the SSH port in /etc/ssh/sshd_config, you need to adjust Zimbra:

zmprov ms zimbra.virtualarchitects.com zimbraRemoteManagementPort 2222

Check /var/log/zimbra.log and /var/log/zimbra-stats.log:

ll /var/log/zimbra*

Are they empty with actual logged detail in dated files? It appears that the logrotate configuration is broken…

/usr/sbin/logrotate -d /etc/logrotate.conf

Run as root:

/opt/zimbra/libexec/zmsyslogsetup

Use of uninitialized value $current_proto in string eq at /usr/lib64/perl5/Sys/Syslog.pm line 371.
Use of uninitialized value $current_proto in string eq at /usr/lib64/perl5/Sys/Syslog.pm line 374.

vim /usr/lib64/perl5/Sys/Syslog.pm

my $current_proto = 0;

If your Zimbra server only has a private IP address and is behind a NAT firewall, you may see errors in /var/log/maillog or /var/log.zimbra.log like:

postfix/lmtp ... status=deferred (connect to your.zimbra.fqdn[your.external.ip.addr]:7025: Connection refused)

See this link to change the way Zimbra resolves the local IP address: http://wiki.zimbra.com/index.php?title=Incoming_Mail_Problems

Assuming a single-server setup with a properly configured /etc/hosts file:

su - zimbra
zmprov ms your.zimbra.fqdn zimbraMtaLmtpHostLookup native
zmmtactl restart

Copy a CoS:

su - zimbra

zmprov cpc <source CoS> <new CoS>

List classes of service:

zmprov gac

Get CoS ID:

zmprov gc <CoS name>|grep zimbraId

Modify the default CoS for a domain:

zmprov md <domain.tld> zimbraDomainDefaultCOSId <your-zimbraId>