Cant Jump ?c# please

so i am making a multiplayer game in photon and when i try and jump i just stay on the ground.

here is my code

 using UnityEngine;
 using System.Collections;
 
 public class ProjectJumpCharacterController : MonoBehaviour {
 //booleans
     public bool issprinting = false;
     public bool ShootingEnabled = false;
     public bool SprintingEnabled = false;
     public bool StaminaEnabled = false;
    
     //floats
     //b
     public float bulletImpulse = 100f;
     //g
     public float gravity = 20;
     //j
     public float jumpHeight = 12;
     //L
     public float lowgravity = 5;
     //m
     public float mouseSensitivity = 6.0f;
     public float  movespeed = 100.0f;
     //n
     public float normalspeed = 250.0f;
     //s
     public float sprintspeed = 500.0f;
     //u
     public float upDownRange = 60.0f;
     //v
     float verticalRotation = 0;
     
     //KeyCodes
     public KeyCode sprint = KeyCode.LeftShift;
 
     //GameObjects
     public GameObject bullet_prefab;
     public GameObject shootfrom;
     
     //Vectors
     private Vector3 amountToMove;
    
     void OnTriggerEnter(Collider other)
     {
         if (other.gameObject.tag == "Low-Gravity")
         {    
             gravity = lowgravity * Time.deltaTime;    
         }
     }
 
     void OnTriggerExit(Collider other)
     {
         if (other.gameObject.tag == "Low-Gravity")
         {
             gravity = 25 *  Time.deltaTime;
         }
     }
     
     void Update()
     {
             //Walking
                 float Fspeed = Input.GetAxis("Vertical") * movespeed * Time.deltaTime;
                 float Sspeed = Input.GetAxis("Horizontal") * movespeed * Time.deltaTime;
         
                 //Declaring our Character Controller and assigning it a name        
                     CharacterController cc = transform.GetComponent<CharacterController> ();
             
                 //Rotation
                 //Rotating the camera
             
                     float rotLeftRight = Input.GetAxis ("Mouse X") * mouseSensitivity;
                     transform.Rotate (0, rotLeftRight, 0);
                     verticalRotation -= Input.GetAxis ("Mouse Y") * mouseSensitivity;
                     verticalRotation = Mathf.Clamp (verticalRotation, -upDownRange, upDownRange);
                     Camera.main.transform.localRotation = Quaternion.Euler (verticalRotation, 0, 0);
             
                 //Sprinting
                 //If the player presses the sprint key it adjusts the move speed of the player 
                 //if stamina is enabled it requires stamina to be > 0 and it depletes stamina when sprinting
         
                 if (Input.GetKey (sprint) && SprintingEnabled == true)
                 {
                         issprinting = true;
                 }
         
                 if (Input.GetKeyUp (sprint))
                 {
                         issprinting = false;
                 }
 
         if (issprinting == true  && SprintingEnabled == true)
         {
             movespeed = sprintspeed;
         }
 
         if (issprinting == false ) 
         {
             movespeed = normalspeed;
         }
         
         //Jumping
         if (cc.isGrounded)
         {
             amountToMove.y = 0;
             
             if (Input.GetButtonDown ("Jump"))
             {
                 amountToMove.y = jumpHeight *Time.deltaTime;    
             }    
         }
         
         if ((cc.collisionFlags & CollisionFlags.Above) != 0)
         { 
             if(amountToMove.y > 0)
             {
                 amountToMove.y =  -gravity;
             }    
         }
            
         //getting the cc to move
         amountToMove.x = Sspeed;
         amountToMove.z = Fspeed;
         amountToMove.y -= gravity;    
         amountToMove = transform.rotation * amountToMove;
         cc.Move (amountToMove);
         
         //Shooting
         if (Input.GetButtonDown ("Fire1") && ShootingEnabled == true)
         {
             GameObject thebullet = (GameObject)PhotonNetwork.Instantiate ("bullet 1", shootfrom.transform.position, shootfrom.transform.rotation, 0);
             thebullet.rigidbody.AddForce (shootfrom.transform.forward * bulletImpulse, ForceMode.Impulse);    
         }
 }

if i remove time.deltatime on the jumping part i go really high really fast and then back down really fast it just pops up and down

i need to fix this fast! please help me