Installation of Plesk Email Security or Plesk Premium Mail extension fails with the following error in Plesk interface:
CONFIG_TEXT: Execution pleskrc has failed with exit code 1, stdout: INFO: [Sat Feb 8 16:52:46 JST 2020]: Service: amavisd, Action: restart
Trying to restart service amavisd... failed
CONFIG_TEXT: Excution package has failed with exit code 1, stdout: , stderr: ERROR:main:Command '['apt-get', '-q', '--assume-yes', '-o', 'Dpkg::Options::=--force-confdef', '-o', 'Dpkg::Options::=--force-confold', '-o', 'APT::Install-Recommends=no', '--purge', 'install', 'amavisd-new']' returned non-zero exit status 100
The output of the command below shows the error:
# journalctl -u amavisd
The value of variable $myhostname is "example", but should have been a fully qualified domain name; perhaps uname(3) did not provide such.
Hostname is not FQDN:
Amavis (the component of Plesk Email Security) requires hostname set up as FQDN to be installed.