Inventory Script Not Working

Hello so recently after many attempts before I finally tried my hardest to understand tutorials on inventory systems. I found a basic script for inventory in one of the tutorials but the script that I am using is not working. (I did attempt to change a few things to fit in my game) I am able to put the item in my inventory list, but when I tried making a key that uses a certain "Potion" all that happens when I click the F key(The Key to use the item) is that it says is this multiple times (NullReferenceException: Object reference not set to an instance of an object Interactable.Update () (at Assets/Scripts/Interactable.cs:40)

Interactable Script

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.AI;
 
 public class Interactable : MonoBehaviour {
     [HideInInspector]
     public NavMeshAgent playerAgent;
     private bool hasInteracted;
     public Inventory inventory;
     public string itemType;
 
     public virtual void MoveToInteraction(NavMeshAgent playerAgent)
     {
         hasInteracted = false;
         this.playerAgent = playerAgent;
         playerAgent.stoppingDistance = 2f;
         playerAgent.destination = this.transform.position;
 
     }
 
     void Update()
     {
         if(!hasInteracted && playerAgent != null && !playerAgent.pathPending)
         {
             if(playerAgent.remainingDistance <= playerAgent.stoppingDistance)
             {
                 Interact();
                 hasInteracted = true;
             }
             else
             {
                 hasInteracted = false;
             }
         }
 
         if (Input.GetButtonDown("Use Potion"))
         {
             //Check the inventory for a potion
             GameObject bottle = inventory.FindItemByType("Health Potion");
             if (bottle != null)
             {
                 //Use the potion
                 Debug.Log("Used Potion");
                 //remove the potion from inventory
                 inventory.RemoveItem(bottle);
             }
         }
     }
 
     public virtual void Interact()
     {
         Debug.Log("Interacting with base class");
     }
 }
 

Potion Script

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Potion : Interactable
 {
 
     public GameObject currentInteractableObject;
     public bool InventoryItem = true;
 
     public override void Interact()
     {
         gameObject.SetActive(false);
         inventory.AddItem(currentInteractableObject);
         Debug.Log("Added Potion");
 
     }
 }

Inventory Script

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Inventory : MonoBehaviour {
 
     public GameObject[] inventory = new GameObject[10];
 
     public void AddItem(GameObject item)
     {
         bool itemAdded = false;
 
         //Find first open slot in inventory
         for (int i = 0; i < inventory.Length; i++)
         {
             if(inventory[i] == null)
             {
                 itemAdded = true;
                 inventory [i] = item;
                 Debug.Log(item.name + "Was Added");
                 break;
             }
         }
         //Inventory Full
         if(!itemAdded)
         {
             Debug.Log("Inventory is Full - Item Not Added");
         }
     }
     public bool FindItem(GameObject item)
     {
         for (int i = 0; i < inventory.Length; i++)
         {
             if (inventory[i] != null)
             {
                 if (inventory[i] == item)
                 {
                     return true;
                 }
             }
         }
         //Item Not Found
         return false;
     }
 
     public GameObject FindItemByType(string itemType)
     {
         for (int i = 0; i < inventory.Length; i++)
         {
             if(inventory [i] !=null)
             {
                 if(inventory[i].GetComponent<Interactable>().itemType == itemType)
                 {
                     //We Found Item of the type we were looking for
                     return inventory[i];
                 }
             }
         }
         //Item of Type not found
         return null;
     }
 
     public void RemoveItem(GameObject item)
     {
         for (int i = 0; i < inventory.Length; i++)
         {
             if(inventory[1] != null)
             {
                 if (inventory[i] == item)
                 {
                     //We Found Item remove it
                     inventory[i] = null;
                     Debug.Log(item.name + "was removed from the inventory");
                     break;
                 }
             }
         }
     }
 }

Thank you for taking the time to look at my scripts and helping me!!