550 Email blocked by combined.rbl.msrbl.net

If emails on your Directadmin server stopped delivering to your users, and the error "550 Email blocked by combined.rbl.msrbl.net" is reported:

Final-recipient: rfc822; user@domain.com
Action: failed
Status: 5.1.1
Diagnostic-Code: smtp; 550 Email blocked by combined.rbl.msrbl.net
Last-attempt-Date: Tue, 13 Jun 2017 13:37:02 +0200

here you will find what you should do.

Why that happened?

The RBL combined.rbl.msrbl.net has stopped working. Your regular emails and senders might still be fine.

What to do?

You need to either remove manually the RBL provider from /etc/exim.conf or upgrade /etc/exim.conf using CustomBuild.

To get the update with CustomBuild 2.0 run the following code as root in conole:

cd /usr/local/directadmin/custombuild
perl -pi -e 's/downloadserver=.*/downloadserver=files1.directadmin.com/' options.conf
./build update
./build exim_conf

Please make sure you don't get the warning saying the following:

You cannot update Exim configuration files, because you do not have it set in options.conf file.

If you do see the the warning then:

• either your exim.conf is customized
• or you simply use the default exim.conf 4.x and did not enable it in options.conf as of yet

If you have the default version of exim.conf simply run:

./build set eximconf yes
./build update
./build exim_conf

If you run a customized version of exim.conf you need to manually remove the combined.rbl.msrbl.net line from your /etc/exim.conf RBL_DNS_LIST entry. First make sure you see combined.rbl.msrbl.net as an output of the following command:

grep combined.rbl.msrbl.net /etc/exim.conf

then run:

perl -pi -e 's|combined.rbl.msrbl.net : \\\n||g' /etc/exim.conf

and check output again (it should be empty this time):

grep combined.rbl.msrbl.net /etc/exim.conf

and restart exim:

service exim restart

Full example from console:

[root@server custombuild]# grep combined.rbl.msrbl.net /etc/exim.conf
       combined.rbl.msrbl.net : \
[root@server custombuild]# perl -pi -e 's|combined.rbl.msrbl.net : \\\n||g' /etc/exim.conf
[root@server custombuild]# service exim restart
Redirecting to /bin/systemctl restart  exim.service
[root@server custombuild]# grep combined.rbl.msrbl.net /etc/exim.conf
[root@server custombuild]#

That's it!