Getting NullReferenceException: Object reference not set to an instance of an object when using Linq reading an xml file.

Hi, I am getting this error even though I am getting value .This is my code:

 public class Assessments : MonoBehaviour {
     public string dataName;
 
     void Start () {
         XElement xDoc = XElement.Load(Application.dataPath + "/XmlDocs/"+dataName+".xml");
         IEnumerable<XElement> AllData = xDoc.Elements();
 
         // Read the entire XML
         foreach (var mentalApplication in AllData)
         {
             string a = mentalApplication.Element("ScoutUser").Value;
             print(a);
         }
     }
 }

Thanks.