Android Webview evaluateJavascript returns null

I am trying to get username from webview. It returns null object.

webView.settings.javaScriptEnabled = true

webView.evaluateJavascript(
                    "(function() { return  document.getElementsByClassName('lgn-loginname') })();",
                    ValueCallback<String> { s ->
                        // 's' contains the result of the JavaScript evaluation
                        Log.d("JavaScript Result", "Result: $s")
                    }
                )

Also with this it is null.

webView.evaluateJavascript(
“(function() { var elements = document.getElementsByClassName(‘lgn-loginname’); ” +
“return elements.length > 0 ? elements[0].innerHTML })();”,
ValueCallback { s ->
// ‘s’ contains the result of the JavaScript evaluation
Log.d(“JavaScript Result”, “Result: $s”)
}
)

I tried many things and always getting null. What am I doing wrong?