MyVestaCP - apt - Debian 10 - Package monit is not available, but is referred to by another package - Решение

Ошибка при установки приложения для мониторинга - monit:

$ apt-get install monit
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package monit is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'monit' has no installation candidate

означает, что на Debian 10 не подключен buster-backports репозиторий. Делаем подключение через отдельный файл:

$ vi /etc/apt/sources.list.d/buster-backports.list
deb http://ftp.de.debian.org/debian buster-backports main

Повторяем установку monit приложения

$ apt update
$ apt install -t buster-backports monit