Mail stuck in queue on Plesk server: delivery temporarily suspended: connect to 127.0.0.1[127.0.0.1]:10024: Connection refused

Symptoms

• E-Mails are stuck in mail-queue on a Plesk server with installed Plesk Email Security extension

• The following error messages appear in /var/log/maillog:

  name postfix/error[14531]: 8954F66E14A4: [email protected], 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)

• The Amavis service is stopped with one of the following errors:

  # 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's hostname is not a fully qualified domain name.

Resolution