What is "Undelivered mail: The Kaspersky Anti-Virus mailbox_count limit is exceeded"?

[iltera]

Hi,

Yesteray night I got a mail notification which had in subject "Undelivered mail", and in the message "The Kaspersky Anti-Virus mailbox_count limit is exceeded".
I have no idea what that means because I am using Kaspersky AntiVirus protection as well as PowerPack. I know powerpack has a limit of 5 mailboxes, but The Kaspersky Antivirus protection should have unlimited mailbox support, right? Then, what is that "mailbox_count limit"?

 

[InderS]

Kaspersky Anti-Virus email service is blocking the mails, try disabling it.