When i jump in front of a wall and going forward, the player go down glitchy (character controller)

When i try to climb a wall of a more height than the max slope variable in the character controller, but if i jump and go forward, the distance from the player and the upper side of the wall its less than max slope, it must be possible to climb, but when i go in front of the wall and hold W and jump, the player goes down quickly and glitchy. Code: using System.Collections; using System.Collections.Generic; using UnityEngine;

public class PlayerMove : MonoBehaviour { private 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;

 float x;
 float z;

 Vector3 velocity;
 bool isGrounded;
 bool canMoveX;

 // Start is called before the first frame update
 private void Awake()
 {
     controller = GetComponent<CharacterController>();
 }

 // Update is called once per frame
 void Update()
 {
     isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);
     

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

     
         if (canMoveX && isGrounded)
         {
             x = Input.GetAxis("Horizontal");
         }
     
         z = Input.GetAxis("Vertical");
     
         


     if (!isGrounded)
     {
         

     
         
         StartCoroutine("CheckIsGrounded");
     }
     
     
     

     Vector3 move = transform.right * x + transform.forward * z;
     
         controller.Move(move * speed * Time.deltaTime);

     

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

     velocity.y += gravity * Time.deltaTime;

     controller.Move(velocity * Time.deltaTime);
 }
 IEnumerator CanMoveX()
 {
     x = 0f;
     yield return new WaitForSecondsRealtime(0.1f);
     canMoveX = true;
 }
 IEnumerator CheckIsGrounded()
 {
     yield return new WaitForSecondsRealtime(0.01f);
     if (isGrounded)
     {
         StartCoroutine("CanMoveX");
     }
     else
     {
         canMoveX = false;
     }
 }
 

}