How can i make my grid controller stop after finding a "wall"

Hello, so i manage to get this script working for me, which gives the exact character movement i want, but the problem is that even after adding a box collider to my character and the same for a wall, the scrip makes the player go through it sorry if this is a silly question but im new to unity and programming. thanks. i leave the code in here.

 using System.Collections;
 using UnityEngine;
 
 class tilemovment : MonoBehaviour {
     private float moveSpeed = 4f;
     private float gridSize = 1f;
     private enum Orientation {
         Horizontal,
         Vertical
     };
     private Orientation gridOrientation = Orientation.Horizontal;
     private bool allowDiagonals = true;
     private bool correctDiagonalSpeed = true;
     private Vector3 input;
     private bool isMoving = false;
     private Vector3 startPosition;
     private Vector3 endPosition;
     private float t;
     private float factor;
 
 
     public void Update() {
         if (!isMoving) {
             input = new Vector3 (Input.GetAxis ("Horizontal"), Input.GetAxis ("forward"));
             if (!allowDiagonals) {
                 if (Mathf.Abs (input.x) > Mathf.Abs (input.y)) {
                     input.y = 0;
                 } else {
                     input.x = 0;
                 }
             }
 
             if (input != Vector3.zero) {
                 StartCoroutine (move (transform));
 
             }
         }
     //    if (Input.GetKey (KeyCode.W)) {
     //        transform.Translate (Vector3.forward);
     //    }
     //    if (Input.GetKey(KeyCode.S)){
     //            transform.Translate(Vector3.back);
     //        }
         
     }
 
     public IEnumerator move(Transform transform) {
         isMoving = true;
         startPosition = transform.position;
         t = 0;
         if(gridOrientation == Orientation.Horizontal) {
             endPosition = new Vector3(startPosition.x + System.Math.Sign(input.x) * gridSize,
                 startPosition.y, startPosition.z + System.Math.Sign(input.y) * gridSize);
         } else {
             endPosition = new Vector3(startPosition.x + System.Math.Sign(input.x) * gridSize,
                 startPosition.y, startPosition.z + System.Math.Sign(input.y) * gridSize);// + System.Math.Sign(input.y) * gridSize, startPosition.z);
         }
         if(allowDiagonals && correctDiagonalSpeed && input.x != 0 && input.y != 0) {
             factor = 0.4071f;
         } else {
             factor = 1f;
         }
         while (t < 1f) {
             t += Time.deltaTime * (moveSpeed/gridSize) * factor;
             transform.position = Vector3.Lerp(startPosition, endPosition, t);
             yield return null;
         }
         isMoving = false;
         yield return 0;
     }
 }