Unable to send or receive email with Plesk Email Security extension installed

Applicable to: Plesk for Linux Symptoms Unable to receive email on the Plesk server, the process fails with the next error message in /var/log/maillog file: CONFIG_TEXT: Jan 6 10:01:30 server amavis[1771804]: (1771804-01) (!)connect_to_sql: unable to connect to DSN 'DBI:MariaDB:database=emailsecurity;mysql_socket=/var/lib/mysql/mysql.sock': Unknown attribute mysql_socket Jan 6 10:01:30 server amavis[1771804]: (1771804-01) (!!)TROUBLE in process_request: connect_to_sql: unable to connect to any dataset at /usr/share/perl5/vendor_perl/Amavis/Out/SQL/Connection.pm line 255. Jan 6 10:01:30 server amavis[1771804]: (1771804-01) (!)Requesting process rundown after fatal error Jan 6 10:01:30 server postfix/smtp[1774083]: 4734718E03471: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10024, delay=0.5, delays=0.47/0/0.01/0.01, dsn=4.3.2, status=deferred (host 127.0.0.1[127.0.0.1] said: 421 4.3.2 Service shutting down, closing channel (in reply to RCPT TO command)) Plesk Email Security extension is installed Installed MariaDB Cause This is a Plesk Email Security product issue with ID #EXTPLESK-10075. The issue was fixed in Plesk Email Security 1.5.23 Resolution Update Plesk Email Security extension to the latest version (1.5.23): Login into Plesk Navigate to Extensions > Updates menu Press Check Now button, then select Plesk Email Security and press on Update button, like on screenshot below: Workaround (if updating PES is not possible for some reason): Connect to the Plesk server via SSH. Using the vi text editor open the /etc/amavisd/email-security.conf file Find and change the value for the mysql_socket to mariadb_socket as below: CONFIG_TEXT: ["DBI:MariaDB:database=emailsecurity;mariadb_socket=/var/lib/mysql/mysql.sock", "es_***", "******"] Save changes Using the vi text editor open the /etc/mail/spamassassin/local.cf Find and change the value for the mysql_socket to mariadb_socket as below: CONFIG_TEXT: bayes_sql_dsn DBI:mysql:emailsecurity:mariadb_socket=/var/lib/mysql/mysql.sock Save changes Restart the Amavis service: # systemctl restart amavisd.service