Why the OnTriggerEnter never detecting ?

On the npc I have a Box Collider Is Trigger is set to false unchecked.
I also have on the npc a Rigidbody both use gravity and is kinematic checked true.
And on the npc also attached this script :

The idea is when the npc hit a door that also have a box collider the npc will stop walking.
I have a parameter in the Animator called Walking Speed set to 1.0 and I want to set it to 0 when colliding with the door but it's never reaching to the OnTriggerEnter in the code I use a break point.

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5.  
6. public class DetectColliders : MonoBehaviour
7. {
8.     private Animator animator;
9.  
10.     private void Start()
11.     {
12.         animator = GetComponent<Animator>();
13.     }
14.  
15.     void OnTriggerEnter(Collider collider)
16.     {
17.         animator.SetFloat("Walking Speed", 0);
18.     }
19. }
20.  

 

Shouldn't npc have Is Trigger checked ?

 

Right. It's working now, Thanks.