How to make camera follow to clone player not first production ?

Hi. I made the code which can follow the clone player. But It worked only the first clone player. If join room second or later, It can't find clone player and doesn't work. How can I fix that ? Thanks for anything your helps.

follow.cs

 private void Awake()
     {
         mainCam = this;
     }
 
     void Start()
     {
         height = Camera.main.orthographicSize;
         width = height * Screen.width / Screen.height;
     }
 
     void LateUpdate()
     {
         if (player == null)
         {
             player = GameObject.Find("Player(Clone)");
         }
         else
         {
             //transform.position = new Vector3(target.position.x, target.position.y, -10f);
 
             transform.position = Vector3.Lerp(transform.position, target.position, Time.deltaTime * speed);
 
             float lx = size.x * 0.5f - width;
             float clampX = Mathf.Clamp(transform.position.x, -lx + center.x, lx + center.x);
 
             float ly = size.y * 0.5f - height;
             float clampY = Mathf.Clamp(transform.position.y, -ly + center.y, ly + center.y);
 
             transform.position = new Vector3(clampX, clampY, -10f);
         }
     }

player spawn script

     public void Spawn()
     {
         GameObject PI = PhotonNetwork.Instantiate("Player", Vector3.zero, Quaternion.identity);
         Follow.mainCam.target = PI.transform;
         
         Debug.Log("I'm in the room.");
     }