A Nessus Daemon is running

The port TCP:3001 or TCP:1241 is open, and since this is the default port for the Nessus daemon, this usually indicates a Nessus daemon is running, and open for the outside world. An attacker can use the Nessus Daemon to scan other site, or to further compromise the internal network on which nessusd is installed on. (Of course the attacker must obtain a valid username and password first, or a valid private/public key)
Block those ports from outside communication, or change the default port nessus is listening on.