trouble with boxcolliders and gravity

hi, I recently started using unity and finally found a tutorial on how to create a move and jump script it works great but the only problem is that if you hold D while touching a vertical surface gravity will slow to a halt , Any help would be appreciated!

Code (CSharp):

1. using UnityEngine;
2.  
3. public class playermv : MonoBehaviour
4. {
5.     public float speed;
6.     public float jump;
7.  
8.     private float move;
9.     private Rigidbody2D rb;
10.     private bool isJumping;
11.  
12.     // Start is called before the first frame update
13.     void Start()
14.     {
15.         rb = GetComponent<Rigidbody2D>();
16.  
17.  
18.     }
19.  
20.     // Update is called once per frame
21.     void Update()
22.     {
23.         move = Input.GetAxisRaw("Horizontal");
24.  
25.         rb.velocity = new Vector2(move * speed, rb.velocity.y);
26.         if (Input.GetButtonDown("Jump") && !isJumping)
27.         {
28.             rb.AddForce(new Vector2(rb.velocity.x, jump));
29.             isJumping = true;
30.  
31.         }
32.     }
33.  
34.     void OnCollisionEnter2D(Collision2D other)
35.     {
36.         if (other.gameObject.CompareTag("Ground"))
37.         {   Debug.Log("isJumping");
38.             isJumping = false;
39.         }
40.  
41.     }
42.  
43. }
44.  
45.