android player error

i have no idea what is wrong . .

 AndroidPlayer(ADB@127.0.0.1:34999)</i> KeyNotFoundException: The given key was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2[System.String,System.Object].get_Item (System.String key) [0x000a2] in /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:150 
   at FacebookScript.<GetFriendsPlayingThisGame>m__2 (IGraphResult result) [0x00018] in D:\CS-GEM-Studios\FootballClicker\Assets\Scripts\FacebookScript.cs:139 
   at Facebook.Unity.AsyncRequestString+<Start>d__9.MoveNext () [0x00000] in <filename unknown>:0 
   at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00028] in /Users/builduser/buildslave/unity/build/Runtime/Export/Coroutines.cs:17 
  
 (Filename: /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs Line: 150)

. .

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using Facebook.Unity;
 using TMPro;
 
 public class FacebookScript : MonoBehaviour {
 
     public TextMeshProUGUI _friendsText;
 
     [SerializeField]
     private GameObject _facebookLoginButton;
 
     private float _refreshTime;
 
     private void Awake()
     {
         if (!FB.IsInitialized)
         {
             FB.Init(() =>
             {
                 if (FB.IsInitialized)
                 {
                     FB.ActivateApp();
                 }
                 else
                 {
                     Debug.Log("Facebook sdk could not initialize");
                 }
             },
             _isGameShown =>
             {
                 if (!_isGameShown)
                 {
                     Time.timeScale = 0;
                 }
                 else
                 {
                     Time.timeScale = 1;
                 }
             }
             );
         }
         else
         {
             FB.ActivateApp();
         }
 
         _refreshTime = 0;
 
     }
 
     private void Update()
     {
         _refreshTime += Time.deltaTime;
 
         if(_refreshTime >= 30)
         {
             Refresh();
             _refreshTime = 0;
         }
     }
 
     private void Refresh()
     {
         CheckIfLoggedIntoFacebook();
         GetFriendsPlayingThisGame();
     }
 
     private void Start()
     {
         CheckIfLoggedIntoFacebook();
     }
 
     #region Facebook log in and out
 
     public void FacebookLogin()
     {
         List<string> permissions = new List<string>() { "public_profile","email","user_friends" };
 
          FB.LogInWithReadPermissions(permissions); // add callbacks
 
 
 
         if(FB.IsLoggedIn)
         {
             GetFriendsPlayingThisGame();
             CheckIfLoggedIntoFacebook();
         }
         else
         {
             CheckIfLoggedIntoFacebook();
         }
     }
 
     public void FacebookLogout()
     {
         FB.LogOut();
     }
 
     #endregion
 
     public void FacebookShare()
     {
         FB.ShareLink(new System.Uri("www.google.com"),"Cool new game!",
             "I just found this awsome new game and I think you should download the game and play it to");
     }
 
     #region Facebook inviting
 
     public void FacebookGameRequest()
     {
         FB.AppRequest("Check out this cool game im playing.", title: "Football clicker!");
     }
 
     public void FacebookCustomGameRequesrt(string Description, string Title)
     {
         FB.AppRequest(Description, title: Title);
     }
 
     public void FacebookInvite()
     {
         FB.Mobile.AppInvite(new System.Uri(""));
     }
 
     #endregion Facebook inviting end
 
     public void GetFriendsPlayingThisGame()
     {
         Debug.Log("Filling friends list");
 
         string query = "/me/friends";
 
         FB.API(query, HttpMethod.GET, result =>
         {
             var _dictionary = (Dictionary<string,object>)Facebook.MiniJSON.Json.Deserialize(result.RawResult);
 
             var _friendsList = (List<object>)_dictionary["data"];
 
             _friendsText.text = string.Empty;
 
             foreach(var _diction in _friendsList)
             {
                 _friendsText.text += ((Dictionary<string,object>)_diction)["name"];
             }
         });
 
         Debug.Log("Friends list populated");
     }
 
     public void CheckIfLoggedIntoFacebook()
     {
         Debug.Log(FB.IsLoggedIn);
 
 
         if (FB.IsLoggedIn)
         {
             _facebookLoginButton.SetActive(false);
         }
         else 
         {
             _facebookLoginButton.SetActive(true);
         }
         
     }
 }