Activate a Unity Timeline from a trigger

GenericTrigger.cs

using UnityEngine;
using UnityEngine.Playables;

public class GenericTrigger : MonoBehaviour
{
    public PlayableDirector timeline;

    // Use this for initialization
    void Start()
    {
        timeline = GetComponent<PlayableDirector>();
    }


    void OnTriggerExit(Collider c)
    {
        if (c.gameObject.tag == "Player")
        {
            timeline.Stop();
        }
    }

    void OnTriggerEnter(Collider c)
    {
        if (c.gameObject.tag == "Player")
        {
            timeline.Play();
        }
    }
}

when my player walks to the trigger nothing happens can you help please