The remote host is vulnerable to a Denial of Service (DoS) attack.
The remote host is running the Alt-N MDaemon mail server. This is a mail server for the Microsoft Windows platform. This version of MDaemon is vulnerable to a flaw where a remote attacker can cause the mail service to crash. An attacker exploiting this flaw would only need to be able to connect to the POP3 port of the server (typically 110). Successful exploitation would result in services being denied to valid users.
Upgrade to version 9.6.1 or higher.