Adding material trough a script,

I'm trying to add a material on my Mesh Renderer through a script. I'm trying to make that when item (weapon) is on a ground it glows and when it's in hand it's normal I have everything set up my 2 materials in a Resources/Materials folder but in console trough Debug.Log and in inspector it shows null/none

I believe error is in Start() function where i try to set variables material and materialA to respective materials. Here is my code: using System.Collections; using System.Collections.Generic; using UnityEngine;

 public class WeaponsPickup : MonoBehaviour
 {
     public Rigidbody rb;
     public BoxCollider coll;
     public Transform player, gunContainer, fpsCam;
     Renderer rend;
     public Material material, materialA;
     public MeshRenderer meshRenderer;
 
     public float pickUpRange, dropForwardForce, dropUpwardForce;
     public bool equipped;
     public static bool slotFull;
 
     private void Start()
     {  
         MeshRenderer meshRenderer = GetComponent<MeshRenderer>();
         Material material = Resources.Load<Material>("Materials/Dungeon_Material_01_A");
         Material materialA = Resources.Load<Material>("Materials/Dungeon_Material_01");
         
         pickUpRange = 1;
         dropUpwardForce = 1;
         dropForwardForce = 3;
        
         player = GameObject.FindGameObjectWithTag("Player").GetComponent<Transform>();
         gunContainer = GameObject.FindGameObjectWithTag("WeaponContainer").GetComponent<Transform>();
         fpsCam = GameObject.FindGameObjectWithTag("MainCamera").GetComponent<Transform>();
         rb = GameObject.FindGameObjectWithTag("Weapon").GetComponent<Rigidbody>();
         coll = GameObject.FindGameObjectWithTag("Weapon").GetComponent<BoxCollider>();
         meshRenderer = GameObject.FindGameObjectWithTag("Weapon").GetComponent<MeshRenderer>();
         
         //Setup
         if (!equipped)
         {
             rb.isKinematic = false;
             coll.isTrigger = false;
         }
         if (equipped)
         {
             rb.isKinematic = true;
             coll.isTrigger = true;
             slotFull = true;
         }
     }
 
     private void Update()
     {
         Debug.Log(material,materialA);
 
         //Check if player is in range and "E" is pressed
         Vector3 distanceToPlayer = player.position - transform.position;
         if (!equipped && distanceToPlayer.magnitude <= pickUpRange && Input.GetKeyDown(KeyCode.E) && !slotFull) PickUp();
 
         //Drop if equipped and "Q" is pressed
         if (equipped && Input.GetKeyDown(KeyCode.Q)) Drop();
     }
 
     private void PickUp()
     {
 
         GetComponent<Renderer>().material = material;
         rb.constraints = RigidbodyConstraints.None;
 
         equipped = true;
         slotFull = true;
 
         //Make weapon a child of the camera and move it to default position
         transform.SetParent(gunContainer);
         transform.localPosition = Vector3.zero;
         transform.localRotation = Quaternion.Euler(Vector3.zero);
         transform.localScale = Vector3.one;
 
         //Make Rigidbody kinematic and BoxCollider a trigger
         rb.isKinematic = true;
         coll.isTrigger = true;
     }
 
     private void Drop()
     {
         
         GetComponent<Renderer>().material = materialA;
         equipped = false;
         slotFull = false;
 
         //Set parent to null
         transform.SetParent(null);
 
         //Make Rigidbody not kinematic and BoxCollider normal
         rb.isKinematic = false;
         coll.isTrigger = false;
 
         //Gun carries momentum of player
         rb.velocity = player.GetComponent<Rigidbody>().velocity;
 
         //AddForce
         rb.AddForce(fpsCam.forward * dropForwardForce, ForceMode.Impulse);
         rb.AddForce(fpsCam.up * dropUpwardForce, ForceMode.Impulse);
         //Add random rotation
         float random = Random.Range(-1f, 1f);
         rb.AddTorque(new Vector3(random, random, random) * 10);
     }
 }
 

Hope this is enough info, Thanks!