How to trigger animation from object colliding with another?

In my project I have the it when you drop Object 1 onto Object 2 it should play the sound of a door opening, as well as play the animation of the door opening. Right now only the sound is playing but not the animation. I have a separate script that plays the door animation by pressing a button which works.

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class CollideDoorOpen : MonoBehaviour {

 public Animator anim; //this is the animation holder where you place the animatior
 public AudioClip SoundToPlay; // audio for the door when it opens
 public AudioSource SoundSource; // the object where the audio comes from
 public bool alreadyPlayed = false; // makes the animation unplayed so it can go off once

 // Start is called before the first frame update
 void Start()
 {
     SoundSource.clip = SoundToPlay; //grabs the audio source that the user puts in and plays from soundsource when triggered
     anim = GetComponent<Animator>(); // grabs the animator
    
 }

   
 void OnCollisionEnter(Collision col)
 {
   if (!alreadyPlayed)
     {
         if (col.gameObject.name == "RedPlatform")
         {
     
            anim.Play("Door_Open"); //runs the door animation
            SoundSource.Play();// plays the audio clip
            alreadyPlayed = true; // once the audio plays the script will turn on already played so it won't play again
         }
     }

 }

 }