Client throwing error Argument out of range error but server working fine

Hi, I'm building a multiplayer game where the environment (made of gameobjects) is destroyed over time. However my code keeps throwing an ArgumentOutOfRangeException: Argument is out of range. Parameter name: index, with a bunch of libraries and things listed underneath but only on the client. As far as i understand it this error corresponds to the list being empty or out of range but i have checked for both (as you can see) and there doesn't seem like there should be a problem. Any help you guys can provide would be great.

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

public class TerrainController : NetworkBehaviour {

 [SerializeField]
 private float timeBeforeStart = 0f;
 [SerializeField]
 private float timeBetweenDestroy = 5f;
 [SerializeField]
 private string tagName = null;

 private List<GameObject> tiles;
 private float counter = 0f;

 private GameObject toDestroy = null;
 private bool startTimeReached = false;

 private void Start()
 {
     tiles = ArrayConverter(GameObject.FindGameObjectsWithTag(tagName));
     Debug.Log(tiles.Count);
 }

 private void Update()
 {
     if (isServer)
     {
         counter += Time.deltaTime;
         //get random character and send to clientRPC
         if (counter >= timeBeforeStart)
         {
             startTimeReached = true;
         }
             if (startTimeReached)
             {
                 if (counter >= timeBetweenDestroy)
                 {
                     counter = 0;
                     int listIndex = Random.Range(0, (tiles.Count - 1));
                     RpcDestroyTile(listIndex);
                     toDestroy = tiles[listIndex];
                     tiles.RemoveAt(listIndex);
                     Destroy(toDestroy);
                 if (tiles.Count == 0)
                 {
                     this.enabled = false;
                 }
             }
             }
     }
 }

 [ClientRpc]
 void RpcDestroyTile(int listIndex)
 {
     if (!isServer)
     {
         toDestroy = tiles[listIndex];
         tiles.RemoveAt(listIndex);
         Destroy(toDestroy);
         if (tiles.Count == 0)
         {
             this.enabled = false;
         }
         Debug.Log("list count:" + tiles.Count + " - index:" + listIndex);
     }
     
 }

 //Loop through an array to put into a list
 public List<GameObject> ArrayConverter(GameObject[] array)
 {
     List<GameObject> list = new List<GameObject>();

     for (int x = 0; x < array.Length; x++)
     {
         list.Add(array[x]);
        
     }

     return list;
 }

}