Why doesn't the script work on base models from the Blender 3D editor?

Question

Unity

I started learning Unity and C# quite recently, I decided to disassemble a very interesting script that gives a jelly effect to a 3D object. But ran into a problem. The script works only on basic 3D objects (cube, cylinder), if I create exactly the same object in a 3D editor (Blender), it refuses to work.
No compilation errors were found, but an error occurs when starting the game.
Not allowed to access vertices on mesh 'Pink(Clone)' (isReadable is false; Read/Write must be enabled in import settings)
UnityEngine.Mesh:set_vertices (UnityEngine.Vector3[])
JellyMesh:FixedUpdate () (at Assets/JellyMesh .cs:35)
Pink is the name of the mesh.
I can't figure out how to allow access to model mesh vertices.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class JellyMesh : MonoBehaviour
{
    public float Intensity = 1f;
    public float Mass = 1f;
    public float stiffness = 1f;
    public float damping = 0.6f;
    private Mesh OriginalMesh = null, MeshClone = null;
    private MeshRenderer renderer;
    private JellyVertex[] jv;
    private Vector3[] vertexArray;
    void Start()
    {
        OriginalMesh = GetComponent<MeshFilter>().sharedMesh;
        MeshClone = Instantiate(OriginalMesh);
        GetComponent<MeshFilter>().sharedMesh = MeshClone;
        renderer = GetComponent<MeshRenderer>();
        jv = new JellyVertex[MeshClone.vertices.Length];
        for (int i = 0; i < MeshClone.vertices.Length; i++)
            jv[i] = new JellyVertex(i, transform.TransformPoint(MeshClone.vertices[i]));
    }
    void FixedUpdate()
    {
        vertexArray = OriginalMesh.vertices;
        for (int i = 0; i < jv.Length; i++)
        {
            Vector3 target = transform.TransformPoint(vertexArray[jv[i].ID]);
            float intensity = (1 - (renderer.bounds.max.y - target.y) / renderer.bounds.size.y) * Intensity;
            jv[i].Shake(target, Mass, stiffness, damping);
            target = transform.InverseTransformPoint(jv[i].Position);
            vertexArray[jv[i].ID] = Vector3.Lerp(vertexArray[jv[i].ID], target, intensity);
        }
        MeshClone.vertices = vertexArray;
    }
    public class JellyVertex
    {
        public int ID;
        public Vector3 Position;
        public Vector3 velocity, Force;
        public JellyVertex(int _id, Vector3 _pos)
        {
            ID = _id;
            Position = _pos;
        }
        public void Shake(Vector3 target, float m, float s, float d)
        {
            Force = (target - Position) * s;
            velocity = (velocity + Force / m) * d;
            Position += velocity;
            if ((velocity + Force + Force / m).magnitude < 0.001f)
                Position = target;
        }
    }
}

I will be grateful for your help!