If it is, it'll be the first time I'm hearing about it, and again if it is, you should be able to resolve it by plugging them both into a switch.
It is not impossible, but it is quite rare.
The first thing to look at will be what are known as link lights, there should be an LED indicator for the NIC, which should light when it is connected to another network device, for the DNS-323, this is on the front panel, the center bottom indicator - if both of those are lit, you have a good connection. If neither is a lit, you have a problem, most likely a bad cable.
In most cases when the easy search utility does not find the NAS, it will be something along the lines of an antivirus, firewall or security suite blocking the connection.