Browser notification not supported

Question

Hi I have simple kotlin webview app for my site my site have push notification an its working in chrome for windows and chrome for android but in my app say not supported this is the image

Image Fome The App

    class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {

    @SuppressLint("SetJavaScriptEnabled", "SdCardPath")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        setSupportActionBar(toolbar)

        webframe.loadUrl(getString(R.string.Site_Url))
        webframe.settings.javaScriptEnabled = true//Enable JavaScript
        webframe.settings.allowFileAccess = true
        webframe.settings.allowFileAccessFromFileURLs = true
        webframe.settings.allowContentAccess = true
        webframe.settings.domStorageEnabled = true
        webframe.settings.setGeolocationEnabled(true)
        CookieManager.getInstance().acceptCookie()
        webframe.restoreState(savedInstanceState)

    }
}