To switch off antivirus protection for a mailbox, perform the following steps:
1 - 1 - Logged in to Plesk, https://your domain name:8443.
2 - Go to Mail.
3 - Click on your mail from the list under Email Addresses tab.
4 - Click on Antivirus tab.
5 - Clear the checkbox Switch on antivirus protection for this email address.
6 - Click OK.