It is impossible to use or update Plesk Email Security extension at Extensions > My Extensions > Plesk Email Security (Open):
PLESK_ERROR: Unsupported operating system: CloudLinux
PLESK_ERROR: Unsupported operating system: AlmaLinux
Emails are stuck in the mail queue and can not be delivered.
Unsupported operating system. The extension is supported on RHEL/CentOS, Debian/Ubuntu only.
Consider installing Plesk on RHEL/CentOS, Debian/Ubuntu, or contact Plesk Sales team for a refund.
To remove the extension:
Go to Extensions > My extensions > click on the Plesk Email Security extension name (not the button Open).
Click More > Remove.
Remove extension via CLI
Connect to the server via SSH.
Run the command:
# plesk bin extension –uninstall email-security
Re-queue all messages stuck in mail queue via:
# postsuper -r ALL
Note: In order to increase probabilities to include Cloud Linux in the list of supported operating systems for the extension, take a part in the product improvement and vote for this feature by following the link: Plesk Email Security for CloudLinux.
The top-ranked suggestions are likely to be included in the next versions of Plesk.