Fix

Assets/Playing room/Scripts/BallThrower.cs

-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using TMPro;
@@ -18,6 +19,9 @@ public class BallThrower : MonoBehaviour
     private bool gameOver = true;
     private float remainingTime;
     private GameObject currentBall;
+    private GameObject ball1;
+    private GameObject ball2;
+    private GameObject ball3;
     private List<GameObject> goList = new List<GameObject>();
 
     private void Start()
@@ -32,7 +36,6 @@ private void SpawnBall(Transform h)
         {
             currentBall = Instantiate(ballPrefab, h.position, Quaternion.identity);
             Rigidbody ballRigidbody = currentBall.GetComponent<Rigidbody>();
-            ballRigidbody.isKinematic = false;
             goList.Add(currentBall);
             currentBall = null;
         }
@@ -49,10 +52,10 @@ private void Update()
         remainingTime -= Time.deltaTime;
         if (remainingTime <= 0)
         {
-            foreach (GameObject obj in goList)
-            {
-                Destroy(obj);
-            }
+            DestroyBalls();
+            //Destroy(ball1);
+            //Destroy(ball2);
+            //Destroy(ball3);
             timerText.text = "0";
             gameOver = true;
         }
@@ -62,6 +65,20 @@ private void Update()
         }
     }
 
+    private void DestroyBalls()
+    {
+        try
+        {
+            foreach (GameObject obj in goList)
+            {
+                Destroy(obj);
+            }
+        }
+        catch (Exception e)
+        {
+            DestroyBalls();
+        }
+    }
     public void StartGame()
     {
         if (!gameOver) return;
@@ -71,6 +88,7 @@ public void StartGame()
         SpawnBall(ballSpawnPos1);
         SpawnBall(ballSpawnPos2);
         SpawnBall(ballSpawnPos3);
+        Debug.LogError(goList);
         remainingTime = startTime;
     }
 }