Imunify extension fails to install packages: Stopped, Error undefined

Symptoms

• On a Plesk server (commonly running on Ubuntu or another Debian-based operating system), the Imunify extension shows the alert Stopped once you open it by going to Plesk > Imunify. Pressing the Retry button displays an empty log window and returns only the following:

  PLESK_ERROR: Error
  undefined

• The same process may get stuck with a different message after reinstalling the extension

  In a few moments the script will install latest imunify-antivirus package (w/dependencies)... (Ctrl-C to cancel)

• The following errors shows up in Plesk in relation to a failed Plesk update attempt:
  

  CONFIG_TEXT: E: The package imunify-common needs to be reinstalled, but I can't find an archive for it.

Cause

Inconsistencies in the system packages and a lack of available source for the reinstallation of the imunify-common package.

Resolution

1. Log into your server via SSH

2. Manually install Imunify with their installation script by executing one of the following commands:

   For ImunifyAV and ImunifyAV+ licenses:

   # wget https://repo.imunify360.cloudlinux.com/defence360/imav-deploy.sh && bash imav-deploy.sh

   For Imunify360 licenses:

   # wget https://repo.imunify360.cloudlinux.com/defence360/i360deploy.sh && bash i360deploy.sh

   Warning: If this fails with en error about alt-python311-libs and gnupg, install the latter manually and rerun the installation script by executing the following command:

   # apt update && apt install -y gnupg && bash imav-deploy.sh || bash i360deploy.sh