Spawning obstacles randomly in 3D endless runner game

Hello everyone. So I managed to create an endless platform but got a problem at spawning obstacles. The problem is obstacles are not spawning around my player, they only appear and disappear in the safezone(in my TileManager script i got a safezone at 30.0f length and 15.0f width so it clons itself and destroys after couple of seconds) Here is my obstacle script

 using System.Collections;
 using UnityEngine;
 public class GameController : MonoBehaviour
 {
     public GameObject obstacle;
     public Vector3 spawnValues;
     public int obstacleCount;
     public float spawnWait;
     public float startWait;
     void Start()
     {
         StartCoroutine (SpawnObstacles());
     }
 
     
     void Update()
     {
         
     }
 
     IEnumerator SpawnObstacles()
     {
         yield return new WaitForSeconds(startWait);
         while (true)
         {
             for (int i = 0; i < obstacleCount; i++)
             {
                 Vector3 spawnPosition = new Vector3(Random.Range(-spawnValues.x, spawnValues.x), spawnValues.y, Random.Range(-spawnValues.z, spawnValues.z));
                 Quaternion spawnRotation = Quaternion.identity;
                 Instantiate(obstacle, spawnPosition, spawnRotation);
                 yield return new WaitForSeconds(spawnWait);
             }
         }
         
         
     }
 }

Can you help me to figure it out ?