question

I followed the tutorial of MR and Azure 303: Natural language understanding (LUIS) https://docs.microsoft.com/en-us/windows/mixed-reality/develop/unity/tutorials/mr-azure-303
In the end, I ended up getting an error on Unity that says

'"Luis Request Exception Message: Object reference not set to an instance of an object
UnityEngine.Debug:Log(Object)
<SubmitRequestToLuis>d__6:MoveNext() (at Assets/Scripts/LuisManager.cs:76)
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)"

I am using a newer version of Unity, could that be the problem ?

My messages are actually showing up on the LUIS portal, so i dont think there's a problem with the endpoint link.

This is the full luisManager code

 using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using UnityEngine;
 using UnityEngine.Networking;
    
 public class LuisManager : MonoBehaviour
 {
     public static LuisManager instance;
    
     //Substitute the value of luis Endpoint with your own End Point
    
     string luisEndpoint = "https://luisinestest.cognitiveservices.azure.com/luis/prediction/v3.0/apps/6d954c3f-9063-4567-8bd8-196a6d1f3171/slots/production/predict?subscription-key=271f533a70fc45dba93d0b4fd8fc2842&verbose=true&show-all-intents=true&log=true&query=";
    
     [Serializable] //this class represents the LUIS response
     public class AnalysedQuery
     {
         public TopScoringIntentData topScoringIntent;
         public EntityData[] entities;
         public string query;
     }
    
     // This class contains the Intent LUIS determines 
     // to be the most likely
     [Serializable]
     public class TopScoringIntentData
     {
         public string intent;
         public float score;
     }
    
     // This class contains data for an Entity
     [Serializable]
     public class EntityData
     {
         public string entity;
         public string type;
         public int startIndex;
         public int endIndex;
         public float score;
     }
    
     private void Awake()
     {
         // allows this class instance to behave like a singleton
         instance = this;
     }
    
     /// <summary>
     /// Call LUIS to submit a dictation result.
     /// The done Action is called at the completion of the method.
     /// </summary>
     public IEnumerator SubmitRequestToLuis(string dictationResult, Action done)
     {
         string queryString = string.Concat(Uri.EscapeDataString(dictationResult));
    
         using (UnityWebRequest unityWebRequest = UnityWebRequest.Get(luisEndpoint + queryString))
         {
             yield return unityWebRequest.SendWebRequest();
    
             if (unityWebRequest.isNetworkError || unityWebRequest.isHttpError)
             {
                 Debug.Log(unityWebRequest.error);
             }
             else
             {
                 try
                 {
                     AnalysedQuery analysedQuery = JsonUtility.FromJson<AnalysedQuery>(unityWebRequest.downloadHandler.text);
    
                     //analyse the elements of the response 
                     AnalyseResponseElements(analysedQuery);
                 }
                 catch (Exception exception)
                 {
                     Debug.Log("Luis Request Exception Message: " + exception.Message);
                 }
             }
    
             done();
             yield return null;
         }
     }
    
    
     private void AnalyseResponseElements(AnalysedQuery aQuery)
     {
         string topIntent = aQuery.topScoringIntent.intent;
    
         // Create a dictionary of entities associated with their type
         Dictionary<string, string> entityDic = new Dictionary<string, string>();
    
         foreach (EntityData ed in aQuery.entities)
         {
             entityDic.Add(ed.type, ed.entity);
         }
    
         // Depending on the topmost recognized intent, read the entities name
         switch (aQuery.topScoringIntent.intent)
         {
             case "ChangeObjectColor":
                 string targetForColor = null;
                 string color = null;
    
                 foreach (var pair in entityDic)
                 {
                     if (pair.Key == "target")
                     {
                         targetForColor = pair.Value;
                     }
                     else if (pair.Key == "color")
                     {
                         color = pair.Value;
                     }
                 }
    
                 Behaviours.instance.ChangeTargetColor(targetForColor, color);
                 break;
    
             case "ChangeObjectSize":
                 string targetForSize = null;
                 foreach (var pair in entityDic)
                 {
                     if (pair.Key == "target")
                     {
                         targetForSize = pair.Value;
                     }
                 }
    
                 if (entityDic.ContainsKey("upsize") == true)
                 {
                     Behaviours.instance.UpSizeTarget(targetForSize);
                 }
                 else if (entityDic.ContainsKey("downsize") == true)
                 {
                     Behaviours.instance.DownSizeTarget(targetForSize);
                 }
                 break;
         }
     }
    
       
 }