StreamReader can't read Android internal storage path

Currently, I am making an Android that will read xml file from a folder in internal storage. Here is how I do it:

 AndroidJavaObject javaObject = new AndroidJavaObject("android.os.Environment");
 string path = "/storage/emulated/0/" + javaObject.GetStatic<string>("DIRECTORY_DOCUMENTS") + "/Stories/Items.xml"; //set Android path
 if (File.Exists(path)) { //check if xml exists in Documents folder
     reader = new StreamReader(path); //set path to reader
     doc.LoadXml(reader.ReadToEnd()); //load external xml
     XmlNodeList nodes = doc.GetElementsByTagName("item");
     LoadData(nodes);
 }

The File.Exists return true, but it seems like the program has stuck at reader = new StreamReader(path). I want my user able to put their own custom xml in a folder outside the Application.persistentDataPath. What can I do to solve it?