Unable to upgrade/install Plesk on Ubuntu/Debian: the following packages have unmet dependencies

Symptoms

Plesk installation or upgrade on Ubuntu/Debian OS fails with the following error:

PLESK_ERROR: Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming.
The following packages have unmet dependencies:
apache2 : Depends: apache2.2-common (= 2.2.22-13+deb7u3) but it is not going to be installed
apache2-mpm-prefork : Depends: apache2.2-common (= 2.2.22-13+deb7u3) but it is not going to be installed
Depends: apache2.2-bin (= 2.2.22-13+deb7u3) but it is not going to be installed
mysql-server : Depends: mysql-server-5.5 but it is not going to be installed
plesk-base : Depends: sw-engine (>= 2.13.8) but it is not going to be installed
plesk-core : Depends: libcurl3 (>= 7.16.2) but it is not going to be installed
awstats : Depends: perl:any
libapache2-mod-bw : Depends: apache2-api-20120211
libapache2-mod-perl2 : Depends: apache2-api-20120211
Depends: libxslt1.1 (>= 1.1.25) but it is not installable
Depends: libmyodbc but it is not installable
Depends: xsltproc but it is not installable
Depends: libtimedate-perl but it is not installable

or

PLESK_ERROR: The apg-get failed with the following message: Reading package lists... Building dependency tree... Reading state information... You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: apache2 :
Depends: apache2-bin (= 2.4.18-2ubuntu3.9) but 2.4.18-2ubuntu3.8 is to be installed
Depends: apache2-data (= 2.4.18-2ubuntu3.9) but 2.4.18-2ubuntu3.8 is to be installed linux-image-virtual:
Depends: linux-image-4.4.0-128-generic but it is not going to be installed plesk-service-node-utilities:
Depends: libidn2-0 (>= 0.6) but it is not going to be installed

Also the following error may appear:

PLESK_ERROR: Enabled repositories check
Plesk installation requires 'Ubuntu/xenial-updates/main' OS repository to be enabled.
Make sure it is available and enabled, then try again.

Cause

Non-standard repositories enabled in /etc/apt/sources.list file that Plesk is not compatible with, so a system cannot resolve all the dependencies properly.

Resolution

1. Connect to the server via SSH.

2. Replace all contents of the file /etc/apt/sources.listwith the default content, like below:

   Default sources.list for:

   Ubuntu 22.04 LTS:

   CONFIG_TEXT: deb http://archive.ubuntu.com/ubuntu/ jammy main restricted universe multiverse
   deb http://archive.ubuntu.com/ubuntu/ jammy-updates main restricted universe multiverse
   deb http://archive.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse
   deb http://archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse
   deb http://archive.canonical.com/ubuntu/ jammy partner

   Ubuntu 20.04 LTS:

   CONFIG_TEXT: deb http://archive.ubuntu.com/ubuntu focal main restricted universe
   deb http://archive.ubuntu.com/ubuntu focal-updates main restricted universe
   deb http://security.ubuntu.com/ubuntu focal-security main restricted universe multiverse
   deb http://archive.canonical.com/ubuntu focal partner

   Ubuntu 18.04 LTS:

   CONFIG_TEXT: deb http://archive.ubuntu.com/ubuntu bionic main restricted universe
   deb http://archive.ubuntu.com/ubuntu bionic-updates main restricted universe
   deb http://security.ubuntu.com/ubuntu bionic-security main restricted universe multiverse
   deb http://archive.canonical.com/ubuntu bionic partner

   Ubuntu 16.04 LTS:

   CONFIG_TEXT: deb http://archive.ubuntu.com/ubuntu xenial main restricted universe
   deb http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe
   deb http://security.ubuntu.com/ubuntu xenial-security main restricted universe multiverse
   deb http://archive.canonical.com/ubuntu xenial partner

   Debian 12.x:

   CONFIG_TEXT: deb http://deb.debian.org/debian bookworm main non-free-firmware
   deb-src http://deb.debian.org/debian bookworm main non-free-firmware
   deb http://deb.debian.org/debian-security/ bookworm-security main non-free-firmware
   deb-src http://deb.debian.org/debian-security/ bookworm-security main non-free-firmware
   deb http://deb.debian.org/debian bookworm-updates main non-free-firmware
   deb-src http://deb.debian.org/debian bookworm-updates main non-free-firmware

   Debian 11.x:

   CONFIG_TEXT: deb http://deb.debian.org/debian bullseye main contrib non-free
   deb-src http://deb.debian.org/debian bullseye main contrib non-free
   deb http://deb.debian.org/debian-security/ bullseye-security main contrib non-free
   deb-src http://deb.debian.org/debian-security/ bullseye-security main contrib non-free
   deb http://deb.debian.org/debian bullseye-updates main contrib non-free
   deb-src http://deb.debian.org/debian bullseye-updates main contrib non-free

   Debian 10.x:

   CONFIG_TEXT: deb http://ftp.debian.org/debian buster main contrib non-free
   deb http://ftp.debian.org/debian buster-updates main contrib non-free
   deb http://security.debian.org buster/updates main contrib non-free

   or:

   CONFIG_TEXT: deb http://deb.debian.org/debian/ buster main non-free contrib
   deb http://security.debian.org/debian-security buster/updates main contrib non-free
   deb http://deb.debian.org/debian/ buster-updates main contrib non-free

   Debian 9.x:

   CONFIG_TEXT: deb http://ftp.debian.org/debian stretch main contrib non-free
   deb http://ftp.debian.org/debian stretch-updates main contrib non-free
   deb http://security.debian.org stretch/updates main contrib non-free

3. Update package lists and install missing dependencies:

   # apt-get update
   # apt-get -f install

4. Run Plesk installation / update / upgrade.