Emails are stuck in queue on a Plesk for Linux server with Plesk Email Security installed: delivery temporarily suspended: connect to 127.0.0.1[127.0.0.1]:10024: Connection refused

Symptoms

• Plesk Email Security extension is installed.

• Emails are stuck in mail queue. The following error messages is logged in /var/log/maillog:

  CONFIG_TEXT: name postfix/error[14531]: 8954F66E14A4: to=jdoe@example.com, relay=none, delay=25755, delays=25754/0.07/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to 127.0.0.1[127.0.0.1]:10024: Connection refused)

• Amavis service is stopped shortly after activation. One of the the following error messages appear either in service status or system log /var/log/syslog:

  # systemctl status amavisd
  (...)
  systemd[1]: Starting Amavis mail content checker...
  name amavisd[1507]: The value of variable $myhostname is "name", but should have been
  name amavisd[1507]: a fully qualified domain name; perhaps uname(3) did not provide such.
  name amavisd[1507]: You must explicitly assign a FQDN of this host to variable $myhostname
  name amavisd[1507]: in amavisd.conf, or fix what uname(3) provides as a host's network name!

  ---

  # systemctl status amavis
  (...)
  name amavis[1108]: Starting amavisd: The value of variable $myhostname is "name", but should have been
  name amavis[1108]: a fully qualified domain name; perhaps uname(3) did not provide such.
  name amavis[1108]: You must explicitly assign a FQDN of this host to variable $myhostname
  name amavis[1108]: in /etc/amavis/conf.d/05-node_id, or fix what uname(3) provides as a host's
  name amavis[1108]: network name!
  name amavis[1108]: (failed).

Cause

The server hostname defined in Amavis configuration is not a fully qualified domain name (FQDN) or is not defined at all.

Resolution

1. Log in to Plesk.

2. Go to Tools & Settings > Server Settings and in Full hostname field

3. Set a fully qualified domain name (FQDN) that resolves to IP address of your Plesk server.

4. Click OK.

5. Connect to your Plesk server via SSH.

6. Set a valid hostname in the system. Replace server.example.com with a hostname defined in Plesk:

   # hostnamectl set-hostname server.example.com

7. Start amavis service:

   # service amavis restart

8. Restart Postfix service:

   # service postfix restart