Imunify360 packages fail to update in Plesk: Failed to fetch (404 Not Found)

Symptoms

• Imunify360 fails to update with errors like the following:

CONFIG_TEXT: 2025-12-24 07:04:36 INFO: pum is called with arguments: ['--update', '--json', '--', 'imunify-antivirus', 'imunify-antivirus-plesk', 'imunify-core', 'imunify-ui', 'imunify-ui-antivirus-plesk', 'imunify-ui-firewall-plesk', 'imunify360-firewall', 'imunify360-firewall-plesk']
2025-12-24 07:04:41 INFO: updating packages: imunify-core imunify-antivirus-plesk imunify-ui-antivirus-plesk imunify360-firewall imunify-ui imunify360-firewall-plesk imunify-antivirus imunify-ui-firewall-plesk
2025-12-24 07:04:41 ERROR: Failed to fetch https://download.imunify360.com/ubuntu/24.04/slot-8/pool/main/i/imunify-antivirus/imunify-antivirus-plesk_8.6.10-1_amd64.deb 404 Not Found [IP: 2001:db8::2 443]
Failed to fetch https://download.imunify360.com/ubuntu/24.04/slot-3/pool/main/i/imunify360-firewall/imunify360-firewall-plesk_8.12.2-2_amd64.deb 404 Not Found [IP: 2001:db8::2 443]
Failed to fetch https://download.imunify360.com/ubuntu/24.04/slot-8/pool/main/i/imunify-antivirus/imunify-antivirus_8.6.10-1_amd64.deb 404 Not Found [IP: 2001:db8::2 443]
Failed to fetch https://download.imunify360.com/ubuntu/24.04/slot-3/pool/main/i/imunify360-firewall/imunify360-firewall_8.12.2-2_amd64.deb 404 Not Found [IP: 2001:db8::2 443]
2025-12-24 07:04:41 ERROR: Exited with returncode 1.

Cause

An issue on the CloudLinux repository side where IPv6 connections to Imunify360 package mirrors intermittently return HTTP 404 responses.

Resolution

Until the problem is fixed on the CloudLinux side, use the following workaround:

1. Connect to the server via SSH.

2. Download the update script:

   # wget -O imunify-force-update.sh https://repo.imunify360.cloudlinux.com/defence360/imunify-force-update.sh

3. Run the update script:

   # bash imunify-force-update.sh