i can't go through level 1 to level 2

im stuck in lvl 1 this is my code ing UnityEngine; using System.Collections; using UnityEngine.SceneManagement;

public class GameManager : MonoBehaviour { public static int currentscore; public static int highscore;

 public static int currentlevel=0;
 public static int unlockedlevel;

 void start()
 {
     DontDestroyOnLoad (gameObject);

 }

 public static void Completelevel()
 {
     
         

         SceneManager.LoadScene (currentlevel+1);
     currentlevel += 1;

     }
 }

using UnityEngine; using System.Collections;

public class PlayerMovement : MonoBehaviour { public float moveSpeed; public GameObject deathpaticles; private float maxspeed=5f; private Vector3 input;

 private Vector3 spawn;

 // Use this for initialization
 void Start () {
     spawn = transform.position;

 
 }

void OnTreiggerEnter(Collider other) { if (other.transform.tag == "goal") { GameManager.Completelevel(); } }