Network.connections.Length is always 0

I have an empty gameObject with a script that contains below code snippet.

void FixedUpdate () {

	if (isServer) {
		Debug.Log ("NCL:" + Network.connections.Length);
	}
}

Everytime a client connects, the above NCL value stays 0.
What can be wrong here?

Network.connections is part of the old/legacy network API.

If you are using UNet, try NetworkServer.connections.