need help with error on questit scripts pick up item

Unity Engine
1

hi im trying to pick up an item from the ground and add it to inventory but when i click the item i get the error:
NullReferenceException
UnityEngine.Camera.ScreenPointToRay (Vector3 position) (at C:/BuildAgent/work/6bc5f79e0a4296d6/Runtime/ExportGenerated/Editor/Graphics.cs:674)
GM+c__Iterator1.MoveNext () (at Assets/QuestIt/Scripts/GM.cs:138)

here is the script at the error

	IEnumerator scanForItems()
	{
		Ray mouseRay;
		RaycastHit hit;
		
		while(true)
		{
            if (Input.GetMouseButtonDown(0))
            {
                mouseRay = Camera.main.ScreenPointToRay(Input.mousePosition);

                if (Physics.Raycast(mouseRay, out hit, 100, ~(1 << 8)))
                {
                    if (hit.transform.GetComponent<item>())
                    {
                        if (IM.Ins.addItemToInventory(hit.transform.GetComponent<item>().itemPtr))
                            Destroy(hit.transform.gameObject);
                        else
                            hit.transform.GetComponent<item>().drop();
                    }
                    else
                    {
                        itemToPickUp = null;
                    }
					
					if (hit.transform.GetComponent<enemyControl>())
					{
						hit.transform.SendMessage("Die");
					}
                }
            }
			
			yield return null;
		}
	}

can anyone help out where it goes wrong

2

NullReference means it’s looking for an object but isn’t finding one. After you’ve destroyed it, maybe something is still looking for it.

3

it happens when i click on the item to add to inventory