Unity Network Connection Does Not Work

Unity cannot use its unique networking system to connect to its own server from other clients.
Currently, there are no errors when playing with the Unity editor, and when connecting locally, the Unity editor and the application built for Windows will be able to synchronize the data well.However, when I try to connect to a network using an IP address from an Android or Windows app, I cannot connect to my server.
Perhaps the problem is that the IP address is not obtained well, but the IP address should be correct because I use my own IP address, which I checked from several IP address verification sites.
Is there any other problem with Unity's network connection?

The following script is used to obtain an IP address:

Development Environment ·OS Windows 10
·Unity 5.6.1f
· VR Application Development with Unity

using System.Collections;
using System.Collections.General;
using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.VR;

public class NetworkStart:NetworkBehavior {
    public GameObject DiveCamera;
    public string hostIP="xxx.xx.xx.xxx";

    void Awake() {
        VRSettings.enabled = false; 

        # if (UNITY_ANDROID||UNITY_IPHONE)
        DiveCamera.SetActive(true);
        NetworkManager net=GetComponent<NetworkManager>();
        net.networkAddress=hostIP;
        net.StartClient();
        # else
        DiveCamera.SetActive(false);
        #endif
    }
}