How do I make my player jump on blocks and not only the surface?

So I am new to unity, I don’t know much but I think this has something to do with groundDistance. Anyways the problem is when I try to jump on block it doesn’t work but when I am on the surface I can jump.

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

public class PlayerMovement : MonoBehaviour
    public CharacterController controller;

    public float speed = 12f;
    public float gravity = -9.81f;
    public float jumpHeight = 3f;

    public Transform groundCheck;
    public float groundDistance = 0.4f;
    public LayerMask groundMask;

    Vector3 velocity;
    bool isGrounded;
    // Update is called once per frame
    void Update()

        isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);

        if(isGrounded && velocity.y < 0)
            velocity.y = -2f;

        float x = Input.GetAxis("Horizontal");
        float z = Input.GetAxis("Vertical");

            Vector3 move = transform.right * x + transform.forward * z;

        controller.Move(move * speed * Time.deltaTime);

        if(Input.GetButtonDown("Jump") && isGrounded)
            velocity.y = Mathf.Sqrt(jumpHeight * -2f * gravity);

        velocity.y += gravity * Time.deltaTime;

        controller.Move(velocity * Time.deltaTime);

Nevermind, I solved it, I just had to set a layer to every block and now it works perfectly.