Why isn't onConfigurationChanged being called?

I'm writing a code that changes the TextView's text when the orientation is changed I am using the onConfigurationChanged() listener for changing the text

override fun onConfigurationChanged(newConfig: Configuration?) {
    super.onConfigurationChanged(newConfig)

    val orientation : Int = getResources().getConfiguration().orientation
    val oTag = "Orientation Change"

    if(orientation == (Configuration.ORIENTATION_LANDSCAPE)){
        mytext?.setText("Changed to Landscape")
        Log.i(oTag, "Orientation Changed to Landscape")

    }else if (orientation == (Configuration.ORIENTATION_PORTRAIT)){
        mytext?.setText("Changed to Portratit")
        Log.i(oTag, "Orientation Changed to Portratit")
    }else{
        Log.i(oTag, "Nothing is coming!!")
    }
}

but nothing happens not even in the Log

also I have added this attribute to my Activity in manifest file

android:configChanges="orientation"

What am I missing here ? also is there any other way to achieve this?