ClamAV antivirus stops frequently and marks emails with "UNCHECKED" tag in Plesk

Symptoms

• Emails are marked with "UNCHECKED" tag in the subject.

• Plesk Premium Email extension is installed.

• The ClamAV service is shown as stopped at Tools & Settings > Plesk Email Security > Dashboard.

  
  
  
  

• The following error message appears in /var/log/syslog:

  # grep -ir "Out of memory" /var/log/syslog
  /var/log/syslog: kernel: [33919.520742] Out of memory: Kill process 1249 (clamd) score 137 or sacrifice child

Cause

The Plesk server does not meet memory requirements for the paid version of Plesk Premium Mail.

Antivirus functionality of Plesk Email Security is resource-intensive. For the service to work correctly, the server should have at least 4 GB of overall memory and 2 GB free memory.

Resolution

Apply one of the following solutions: