Why collisions on meshcollider 2d doesn't work?

Hello, I want to generate random terrain with collisions and I use mesh generator from Unity Wiki for it. It works fine.

Now I want to add collisions and I found the same problem here https://answers.unity.com/questions/171571/dynamic-mesh-collider.html

but answer doesn't work for me.

I have gameObject with attached script to it, but when other gameObjects goes through Mesh object, collision doesn't happen

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PolygonTester : MonoBehaviour {
     void Start () {
         // Create Vector2 vertices
         Vector2[] vertices2D = new Vector2[] {
             new Vector2 (0, 0),
             new Vector2 (0, 1),
             new Vector2 (1, 1),
             new Vector2 (1, 2),
             new Vector2 (0, 2),
             new Vector2 (0, 3),
             new Vector2 (3, 3),
             new Vector2 (3, 2),
             new Vector2 (2, 2),
             new Vector2 (2, 1),
             new Vector2 (3, 1),
             new Vector2 (3, 0),
         };
 
         // Use the triangulator to get indices for creating triangles
         Triangulator tr = new Triangulator (vertices2D);
         int[] indices = tr.Triangulate ();
 
         // Create the Vector3 vertices
         Vector3[] vertices = new Vector3[vertices2D.Length];
         for (int i = 0; i < vertices.Length; i++) {
             vertices[i] = new Vector3 (vertices2D[i].x, vertices2D[i].y, 0);
         }
 
         // Create the mesh
         Mesh msh = new Mesh ();
         msh.vertices = vertices;
         msh.triangles = indices;
         msh.RecalculateNormals ();
         msh.RecalculateBounds ();
 
         // Set up game object with mesh;
         gameObject.AddComponent (typeof (MeshRenderer));
         MeshFilter filter = gameObject.AddComponent (typeof (MeshFilter)) as MeshFilter;
         filter.mesh = msh;
 
         MeshCollider myMC = GetComponent<MeshCollider> ();
         myMC.sharedMesh = null;
         myMC.sharedMesh = msh;
     }
 }