If Plesk Premium Antivirus is sending notifications stating that the virus bases are obsolete, it means that the antivirus definitions (also known as virus signatures) are outdated. This can happen if the automatic updates for the antivirus are not functioning correctly.

Here's how you can address this issue:

1. Update the Antivirus Definitions Manually:

   • In Plesk, go to Extensions > My Extensions > Premium Antivirus. From there, click on the "Refresh" button to manually update the antivirus definitions.

2. Check for Updates in the Plesk Extension Catalog:

   • Go to Extensions > Extension Catalog and find the Premium Antivirus extension. Check if there are any updates available for it. If so, install the latest version.

3. Check for Internet Connectivity:

   • Ensure that your server has a stable internet connection. The antivirus needs to connect to the internet to download the latest definitions.

4. Verify Firewall Rules:

   • If you have a firewall in place, make sure it allows outgoing connections to the necessary servers where the antivirus definitions are hosted.

5. Check for Cron Job Errors:

   • If you're using a Linux server, Plesk might be using a scheduled task (cron job) to update the antivirus definitions. Check if there are any errors related to the antivirus in the cron job logs.

6. Reinstall or Repair the Antivirus Extension:

   • In some cases, reinstalling or repairing the Premium Antivirus extension in Plesk might resolve the issue. You can do this from Extensions > My Extensions.

7. Review License and Subscription:

   • Ensure that your Premium Antivirus license is active and up-to-date. If it has expired or there are issues with the subscription, it might affect the ability to download updates.

8. Contact Plesk Support:

   • If none of the above steps resolve the issue, consider reaching out to Plesk support for further assistance. They can provide specific guidance based on your server's configuration.

It's crucial to keep antivirus definitions up-to-date to ensure optimal protection against the latest threats. Regularly checking for updates and resolving any issues with the update process will help maintain a secure environment.