Facebook SDK Session(UNITY)

I'm creating a LOGIN system using FACEBOOK SDK 7.4.0 version and Unity 5.6.3P2. It successfully gets the information i needed when i first login . I have 2 problems with the FACEBOOK SDK actually.

When i logout it successfully return to my landing menus. Now the problem occurs here because when i try to login again it doesn't work anymore it keeps on popping like this.

Here's my code so far.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 //include for facebook namespace
 using Facebook.Unity;

 public class FBManager : MonoBehaviour {

 public GameObject LoggedIn;
 public GameObject LoggedOut;
 public GameObject ProfilePicture;
 public GameObject username;

 public Text Status;
 //Button for the Google Account
 public GameObject GoogleAccount; /*Just uses this for the setActive of the button */
 //Button for the Local Account    
 public GameObject LocalAccount; /*disable this*/
 //Button for the playstore
 public GameObject PlayStoreAccount; /*disable this*/

 void Awake(){
     FB.Init (OnSetInit, OnHideUnity);
 }

 void OnSetInit(){
     if (FB.IsLoggedIn) {
         Debug.Log ("FB is Logged in");
         Status.text = "FB is Logged In";
     } else {
         Debug.Log ("FB is not Logged in");
         Status.text = "FB is not Logged In";
     }
     DealWithFBMenus (FB.IsLoggedIn);
 }

 void OnHideUnity(bool isGameShown){
     if (!isGameShown) {
         Time.timeScale = 0;
     } else {
         Time.timeScale = 1;
     }
 }

 public void FbLogin(){
     List<string> permissions = new List<string> ();

     //ask for public profile
     permissions.Add("public_profile");

     FB.LogInWithReadPermissions (permissions, AuthCallBack);
 }

 public void FbLogout(){
     List<string> permission = new List<string> ();

     FB.LogOut ();
     //remove public Profile
     permission.Remove("public_profile");
     DealWithFBMenus (FB.IsLoggedIn);
     Debug.Log ("FB is Logged Out");
     Status.text = "FB is Logged Out";

 }

 void AuthCallBack(IResult result){
     if (result.Error != null) {
         Debug.Log (result.Error);

     } else {
         if (FB.IsLoggedIn) {
             Debug.Log ("FB is Logged in");
             Status.text = "FB is Logged In";
         } else {
             Debug.Log ("FB is not Logged in");
             Status.text = "FB is not Logged In";
         }
         DealWithFBMenus (FB.IsLoggedIn);
     }
 }

 void DealWithFBMenus(bool isLoggedIn){
     if (isLoggedIn) {
         LoggedIn.SetActive (true);
         LoggedOut.SetActive (false);
         GoogleAccount.SetActive (false);
         LocalAccount.SetActive (false);
         PlayStoreAccount.SetActive (false);
         FB.API ("/me?fields=first_name", HttpMethod.GET, DisplayUsername);
         FB.API ("/me/picture?type=square&height=128&width=128", HttpMethod.GET, DisplayProfilePic);
     } else {
         LoggedIn.SetActive (false);
         LoggedOut.SetActive (true);
         GoogleAccount.SetActive (true);
         LocalAccount.SetActive (true);
         PlayStoreAccount.SetActive (true);
     }
 }

 void DisplayUsername(IResult result){
     Text UserName = username.GetComponent<Text> ();

     if (result.Error == null) {
         UserName.text = "hi there " + result.ResultDictionary ["first_name"]; 
     } else {
         Debug.Log (result.Error);
     }
 }

 void DisplayProfilePic(IGraphResult result){
     Image ProfilePic = ProfilePicture.GetComponent<Image> ();
     if (result.Texture != null) {

         ProfilePic.sprite = Sprite.Create (result.Texture, new Rect (0, 0, 128, 128), new Vector2 ());

     } else {

         Destroy (ProfilePic.sprite);
     }
 }
 }