MissingReferenceException: The object of type 'Transform'

MissingReferenceException: The object of type 'Transform' has been destroyed but you are still trying to access it. Your script should either check if it is null or you should not destroy the object. UnityEngine.Transform.get_position () (at :0) Enemy.Pursueplayer () (at Assets/Scripts/Enemy.cs:47) Enemy.Update () (at Assets/Scripts/Enemy.cs:41)

using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.AI;

 public class Enemy : MonoBehaviour
 {
     [Header("Enemy Health and Damage")]
     public float giveDamage = 5f;
     public float enemySpeed;
 
     [Header("Enemy Things")]
     public NavMeshAgent enemyAgent;
     public Transform LookPoint;
     public GameObject ShootingRaycastArea;
     public Transform playerBody;
     public LayerMask PlayerLayer;
 
 
     [Header("Enemy Shooting Var")]
     public float timebtwshoot;
     bool previouslyShoot;
 
     [Header("Enemy States")]
     public float visionRadius;
     public float shootingRadius;
     public bool playerInvisionRadius;
     public bool playerInshootingRadius;
     public bool isPlayer = false;
 
     private void Awake()
     {
         enemyAgent = GetComponent<NavMeshAgent>();
     }
 
     private void Update()
     {
         playerInshootingRadius = Physics.CheckSphere(transform.position, visionRadius, PlayerLayer);
         playerInshootingRadius = Physics.CheckSphere(transform.position, shootingRadius, PlayerLayer);
 
         if(playerInvisionRadius && !playerInshootingRadius) Pursueplayer();
         if(playerInshootingRadius && playerInshootingRadius) ShootPlayer();
     }
 
     private void Pursueplayer()
     {
         if(enemyAgent.SetDestination(playerBody.position))
         {
             //animations
         }
     }
 
     private void ShootPlayer()
     {
         enemyAgent.SetDestination(transform.position);
 
         transform.LookAt(LookPoint);
 
         if (!previouslyShoot)
         {
             RaycastHit hit;
 
             if (Physics.Raycast(ShootingRaycastArea.transform.position, ShootingRaycastArea.transform.forward, out hit, shootingRadius))
             {
                 Debug.Log("Shooting" + hit.transform.name);
 
                 PlayerScript playerBody = hit.transform.GetComponent<PlayerScript>();
 
                 if(playerBody != null)
                 {
                     playerBody.playerHitDamage(giveDamage);
                 }
 
 
             }
 
             previouslyShoot = true;
             Invoke(nameof(ActiveShooting), timebtwshoot);
         }
     }
 
      private void ActiveShooting()
     {
         previouslyShoot = false;
     }
 
 }