Subscribe user and get Notify when user register or unregister

Question

I want to subscribe presence and dialog of all sip user and get notify when user on call , available, on ringing and unregister.

I am using sip.js with reactjs.

SIPJS : "sip.js": "^0.20.0",

Code :

UserAgent :

`const userOptions: UserAgentOptions = {
            uri: UAURI,
            authorizationPassword: password,
            authorizationUsername: username,
            contactName: username,
            viaHost: domain,
            transportOptions: {
                server: server,
                traceSip: true,
            },
            delegate: { onInvite, onNotify },
            register: true,
            noAnswerTimeout: 60,
            userAgentString: "A | B ",
            dtmfType: "info",
            displayName: "WEBRTC",
            activeAfterTransfer: false, //  Die when the transfer is completed
            logBuiltinEnabled: true, // Boolean - true or false - If true throws console logs
        };
        console.log( userOptions );
        userAgent = new UserAgent( userOptions );

        console.log( "USSSSSEEERRR AGENT" );
        console.log( userAgent );`

After Register Subscribe another users :

`const Subscribe = () => {

        console.log("useragentstate");
        console.log(userAgent);
        
        
        

        const dialogOptions = {
            extraHeaders: [
              "Accept: application/pidf+xml"
            ],
          };
        const targetURI = new URI("sip", "10019", "example.com");
        const eventType = "presence"; 
        const subscriber = new Subscriber(userAgent, targetURI, eventType, dialogOptions);
        

        subscriber.delegate = {
            onNotify: (notification: Notification) =>
            {
                // here you can get the NOTIFY body and parse it to get the users inside the conference...
                console.log("COMING FOR NOTIFY");
                notification.accept();
            }
        };
        console.log(subscriber);
        subscriber.subscribe();


    };`

After subscribe that notify not getting for user 10019. User = 10020 -> subscribe -> 10019 Server = Accepted -> User

But after that Notify not getting like below : From 10019 -> 10020 (Register / Unregister)

Please any one help that what i have missing on subscribe or useragent register option that help me solve the problem.