I am not able to reload a Scene a second time for my game

I have not used any static variables, nor have i used any of the DontDestroyOnLOad.

My scripts are as following

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

public class DragonScript : MonoBehaviour {

 public Rigidbody2D myRigidBody;
 public Animator myAnimator;
 public float jumpForce;
 public bool isAlive;
 



 // Use this for initialization
 void Start () {

     isAlive = true;

     myRigidBody = gameObject.GetComponent<Rigidbody2D>();
     myAnimator = gameObject.GetComponent<Animator>();

     jumpForce = 10f;
     myRigidBody.gravityScale = 5f;

     
 }
 
 // Update is called once per frame
 void Update () {
     isAlive = true;
     if (isAlive)
     {
         if (Input.GetMouseButton(0))
         {
             Flap();
         }
         CheckIfDragonisVisibleOnScreen();
     }
     
 }


 void Flap()
 {
     myRigidBody.velocity =
         new Vector2(0, jumpForce);

     myAnimator.SetTrigger("Flap");
 }



 private void OnCollisionEnter2D(Collision2D target)
 {
    
     if(target.gameObject.tag == "Obstacles")
     {
         isAlive = false;
         Time.timeScale = 0f;
     }
 }

 void CheckIfDragonisVisibleOnScreen()
 {
     if (Mathf.Abs(gameObject.transform.position.y) > 5.4f)
     {
         isAlive = false;
         Time.timeScale = 0f;
     }
 }

   

}

above was for flapping dragon animation

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

public class ObstacleScript : MonoBehaviour { Rigidbody2D myRigidbody; float dragonXposition; bool isScoreAdded;

 GameManagerScript gameManager;

 // Use this for initialization
 void Start () {

     myRigidbody = gameObject.GetComponent<Rigidbody2D>();
     myRigidbody.velocity = new Vector2(-2.5f, 0);

     dragonXposition =
         GameObject.Find("Dragon").transform.position.x;

     isScoreAdded = false;

     gameManager = GameObject.Find("GameManager")
         .GetComponent<GameManagerScript> ();
         
 }
 
 // Update is called once per frame
 void Update () {
     if(transform.position.x<=dragonXposition)
     {
         
         if(!isScoreAdded)
         {
             AddScore();
             isScoreAdded = true;
         }
     }

     if (transform.position.x <= -10f)
     {
         Destroy(gameObject);
     }
 }

 void AddScore()
 {
     gameManager.GmAddScore();
 }

 

}

This one is for obstacles

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

public class ObstacleScript : MonoBehaviour { Rigidbody2D myRigidbody; float dragonXposition; bool isScoreAdded;

 GameManagerScript gameManager;

 // Use this for initialization
 void Start()
 {

     myRigidbody = gameObject.GetComponent<Rigidbody2D>();
     myRigidbody.velocity = new Vector2(-2.5f, 0);

     dragonXposition =
         GameObject.Find("Dragon").transform.position.x;

     isScoreAdded = false;

     gameManager = GameObject.Find("GameManager")
         .GetComponent<GameManagerScript>();

 }

 // Update is called once per frame
 void Update()
 {
     if (transform.position.x <= dragonXposition)
     {

         if (!isScoreAdded)
         {
             AddScore();
             isScoreAdded = true;
         }
     }

     if (transform.position.x <= -10f)
     {
         Destroy(gameObject);
     }
 }

 void AddScore()
 {
     gameManager.GmAddScore();
 }

  

}

This is game manager

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

public class MenuCtrl1 : MonoBehaviour {

 // Use this for initialization
 public void LoadScene(string sceneName)
 {
    
     SceneManager.LoadScene(sceneName);
    

 }

}

and last one is to change scenes

please correct the codes where possible