Question Why my Debug.DrawLine doesn't show up?

For my project I am using Area Target and baked NavMesh as a path. I have been terribly frustrated with the Debug.DrawLine. I just using scripting API by Unity but I don't know why it doesn't show up. I try use another project which is on cube object as a NavMesh path suddenly it show up.

So this is the script that I used which is from Unity.

Code (CSharp):

1. // ShowGoldenPath
2. using UnityEngine;
3. using UnityEngine.AI;
4.  
5. public class ShowGoldenPath : MonoBehaviour
6. {
7.     public Transform target;
8.     private NavMeshPath path;
9.     private float elapsed = 0.0f;
10.     void Start()
11.     {
12.         path = new NavMeshPath();
13.         elapsed = 0.0f;
14.     }
15.  
16.     void Update()
17.     {
18.         // Update the way to the goal every second.
19.         elapsed += Time.deltaTime;
20.         if (elapsed > 1.0f)
21.         {
22.             elapsed -= 1.0f;
23.             NavMesh.CalculatePath(transform.position, target.position, NavMesh.AllAreas, path);
24.         }
25.         for (int i = 0; i < path.corners.Length - 1; i++)
26.             Debug.DrawLine(path.corners[i], path.corners[i + 1], Color.red);
27.     }
28. }

Is there anyone knows why it doesn't show up? Supposedly it shows from bottom of the camera to another gameObject.

Or it has something missing that I don't know in order to setup the Area Target and AI navigation?