The extension Imunify shows an error in Plesk: Imunify agent is not running

Gabriel Aznarez

Updated November 28, 2025 19:42

kb: technical

Symptoms

While navigating to Plesk > Imunify an error is shown in the extension:

Imunify agent is not running
The imunify360 service is not running and can not be started:

# systemctl status imunify360.service
● imunify360.service - Imunify360 resident
Loaded: loaded (/lib/systemd/system/imunify360.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Thu 2025-12-01 11:09:46 CET; 3min 52s ago
...
systemd[1]: Failed to start Imunify360 resident.
The following error might be found in the /var/log/imunify360/error.log log file:

FileNotFoundError: [Errno 2] No such file or directory: '/etc/sysconfig/imunify360/.go_agent
Either the file or the entire directory from the previous error does not exist:

# ls -l /etc/sysconfig/imunify360/
ls: cannot access '/etc/sysconfig/imunify360/': No such file or directory

The Imunify extension installation is corrupted.

Reinstall the Imunify extension.

In case the installation fails with 'E: The value 'buster-backports' is invalid for APT'

Apply the following steps in case that the installation fails with:

E: The value 'buster-backports' is invalid for APT::Default-Release as such a release is not available in the sources

Add the following repository in the /etc/apt/source.list file. Vi editor can be used for this:

# deb http://archive.debian.org/debian buster-backports main contrib non-free
Remove old Imunify packages:

# apt-get purge imunify*
Install the extension via cli command:

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