Question 'SetDestination' can only be called on an active agent that has been placed on a NavMesh.

I was following this tutorial
https://www.bing.com/videos/search?...-20&sk=&cvid=01447386E6EA456CBC1D8E250CB06138
I know its a bit out of date but I was just trying to get an ai to follow me. Here is my script

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5. using UnityEngine.AI;
6.  
7. public class EnemyController : MonoBehaviour
8. {
9.     public float lookRadius = 10f;
10.  
11.     Transform target;
12.     NavMeshAgent agent;
13.  
14.     // Start is called before the first frame update
15.     void Start()
16.     {
17.         target = PlayerManager.instance.player.transform;
18.         agent = GetComponent<NavMeshAgent>();
19.     }
20.  
21.     // Update is called once per frame
22.     void Update()
23.     {
24.         float distance = Vector3.Distance(target.position, transform.position);
25.  
26.         if (distance <= lookRadius)
27.         {
28.             agent.SetDestination(target.position);
29.         }
30.     }
31.  
32.     void OnDrawGizmosSelected()
33.     {
34.         Gizmos.DrawWireSphere(transform.position, lookRadius);
35.     }
36. }
37.  

The error code

 

This means you haven't baked your scene/map. Go to the navigation tab, and go to 'Bake', and then bake it. Here is more info
https://docs.unity3d.com/Manual/nav-BuildingNavMesh.html