Server with Plesk Email Security no longer sends/receives emails: [127.0.0.1]:10024: Connection refused

Applicable to: Plesk Obsidian for Linux Symptoms Server with Plesk Email Security no longer sends/receives emails Emails remain in the mail-queue at Tools & Settings > Mail Server Settings > Mail Queue Plesk Email Security was recently updated to version 1.1.1-223 as per Tools & Settings > Action log: CONFIG_TEXT: 'Upgrade extension' ('Extension Id': 'email-security' => 'email-security', 'Extension Name': 'Plesk Email Security' => 'Plesk Email Security', 'Extension Release': '216' => '223', 'Extension Version': '1.1.0' => '1.1.1') In mailserver logs under /var/log/maillog the below message also can be found: CONFIG_TEXT: Aug 5 15:50:37 server postfix/error[5528]: A898A3FEA9: [email protected], relay=none, delay=0.19, delays=0.18/0.01/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to 127.0.0.1[127.0.0.1]:10024: Connection refused) Cause Product issue: #EXTCERT-3028 "Postfix strict rules are not applied automatically and are removed in the update process" Fixed in: Plesk Email Security 1.1.2-224 06 August 2020 Resolution Update Plesk Email Security extension. Open the extension to install the required components by going to Extensions > My Extensions > Plesk Email Security>Install Connect to the server via SSH Re-queue emails: # postsuper -r ALL If the same issue exists but another steps are needed to fix the issue, for example re-install PES extension then create a new article. Most probably it has another cause that should be found.