Error pls help

@corns

Help I don't know what i did wrong. I got this error: Assets/scripts/player.cs(81,28): error CS1061: Type Gamemaneger' does not contain a definition for RestartGame' and no extension method RestartGame' of type Gamemaneger' could be found (are you missing a using directive or an assembly reference?) Scripts:

Player script:

using UnityEngine;

using System.Collections;

public class player : MonoBehaviour { public float moveSpeed; public float JumpForce;

 public float jumpTime;
 private float jumpTimeCounter;

 private Rigidbody2D myRigidbody;


 public bool grounded;
 public LayerMask whatisground;
 public Transform groundcheck;
 public float radius;

 private Collider2D mycollider;

 private Animator myanimator;

 public Gamemaneger theGamemanager;

 // Use this for initialization
 void Start () {
     myRigidbody = GetComponent<Rigidbody2D>();

     mycollider = GetComponent<Collider2D>();

     myanimator = GetComponent<Animator>();

     jumpTimeCounter = jumpTime;
 }
 
 // Update is called once per frame
 void Update () {

     //grounded = Physics2D.IsTouchingLayers(mycollider, whatisground);

     grounded = Physics2D.OverlapCircle(groundcheck.position, radius, whatisground);

     myRigidbody.velocity = new Vector2(moveSpeed, myRigidbody.velocity.y);

     if(Input.GetKeyDown(KeyCode.Space) || Input.GetMouseButtonDown(0))
     {
         if(grounded)
         {
             myRigidbody.velocity = new Vector2(myRigidbody.velocity.x, JumpForce);
         }
     }

     if (Input.GetKey (KeyCode.Space) || Input.GetMouseButton(0))
     {
         if(jumpTimeCounter > 0)
         {
             myRigidbody.velocity = new Vector2(myRigidbody.velocity.x, JumpForce);
             jumpTimeCounter -= Time.deltaTime;
         }
     }

     if(Input.GetKeyUp (KeyCode.Space) || Input.GetMouseButtonUp(0))
     {
         jumpTimeCounter = 0;
     }

     if(grounded)
     {
         jumpTimeCounter = jumpTime;
     }
         

     myanimator.SetFloat("snelheid", myRigidbody.velocity.x);
     myanimator.SetBool("Grounded", grounded);
 } 

 void OnCollisionEnter2D (Collision2D other)
 {
     if(other.gameObject.tag == "killbox")
     {
         theGamemanager.RestartGame();
     }
 }

}

Gamemaneger script:

using UnityEngine; using System.Collections; using System;

public class Gamemaneger : MonoBehaviour {

 public Transform Platformgenerator;
 private Vector3 platformStartpoint;

 public player thePlayer;
 private Vector3 playerStartPoint;

 // Use this for initialization
 void Start () {
     platformStartpoint = Platformgenerator.position;
     playerStartPoint = thePlayer.transform.position;
 }
 
 // Update is called once per frame
 void Update ()
 { }

 public void RestartGame()
 {
     StartCoroutine(RestartGameCo());
 }

 public IEnumerator RestartGameCo()
 {
     thePlayer.gameObject.SetActive(false);
     yield return new WaitForSeconds(0.5f);
     thePlayer.transform.position = playerStartPoint;
     Platformgenerator.position = platformStartpoint;
     thePlayer.gameObject.SetActive(true);
 }

}