Character Controller problem

I have problem with character controller

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. public class Player : MonoBehaviour
5. {
6.     CharacterController characterController;
7.     public float speed = 6.0f;
8.     private Vector3 moveDirection = Vector3.zero;
9.     Rigidbody rigidbody;
10.     Animator animator;
11.     void Start()
12.     {
13.         characterController = GetComponent<CharacterController>();
14.         animator = GetComponent<Animator>();
15.     }
16.     // Update is called once per frame
17.     void Update()
18.     {
19.         if (characterController.isGrounded)
20.         {
21.             animator.SetBool("Run",false);
22.  
23.             moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0.0f, Input.GetAxis("Vertical"));
24.             moveDirection *= speed;
25.             if (Input.GetAxis("Horizontal") != 0 || Input.GetAxis("Vertical") != 0){
26.                 animator.SetBool("Run",true);
27.             }
28.  
29.             if(Input.GetAxis("Vertical") < 0){
30.                 this.transform.rotation = Quaternion.Euler(0,180,0);
31.             }else{
32.                 this.transform.rotation = Quaternion.Euler(0,0,0);
33.             }
34.         }
35.         characterController.Move(moveDirection * Time.deltaTime);
36.     }
37. }
38.  

Is there anything wrong?