Facebook Profile pic Callback don't Execute

Hi, I'm trying to get the user's profile pic and my "ProfilePicCallback" it's not getting executed. What am I Missing?

P.S. This code works perfectly inside unity editor and I can get the name and picture of the user however when I test on iOS the PictureCallback never gets executed and I can only get the username.

This is my code:

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;


 public class FacebookLoginOpt : MonoBehaviour 
 {
 //Diccionario para obtener los datos del usuario de Facebook
 IDictionary dict;

 public GameObject fbLoginBtn;

 private string fbName;

 private GameObject loginCanvas;


 public void FBLogin()
 {
     if (!FB.IsLoggedIn) 
     {
         if (InternetConnection.control.IsConnectedToInternet ()) {
             //Login With Facebook
             FB.Login ("public_profile,user_friends,user_birthday,publish_actions", LoginCallback);
             fbLoginBtn.GetComponent<Button> ().enabled = false;
         } else {

             //Instantiate Facebook Login Canvas
             GameObject thePrefab;
             GameObject getPrefab = Resources.Load <GameObject> ("MyPrefabs/Facebook_Failed_Canvas");
             thePrefab = (GameObject)Instantiate (getPrefab, transform.position,transform.rotation);
             fbLoginBtn.GetComponent<Button> ().enabled = true;


         }
     }
 }

 void LoginCallback(FBResult result)
 {
     if (FB.IsLoggedIn) 
     {
         GetUserData ();
     }
 }

 void GetUserData()
 {
     FB.API ("/me?fields=id,first_name,last_name,gender,birthday,relationship_status", Facebook.HttpMethod.GET, GetUserDataCallback);

     //Get Profile Pic
     FB.API (Util.GetPictureURL ("me", 128, 128), Facebook.HttpMethod.GET,ProfilePicCallback );

     //Instantiate Canvas
     GameObject thePrefab;
     GameObject getPrefab = Resources.Load <GameObject> ("MyPrefabs/Activity_Canvas");
     thePrefab = (GameObject)Instantiate (getPrefab, transform.position,transform.rotation);


 }

 void GetUserDataCallback(FBResult result)
 {
     if(result.Error != null)
     {
         FB.API ("/me?fields=id,first_name,last_name,gender,birthday,relationship_status", Facebook.HttpMethod.GET, GetUserDataCallback);
         Debug.Log("Se quedó en estancado");
         Debug.Log(result.Error);
         return;
     }

     Destroy (GameObject.Find ("Activity_Canvas(Clone)").gameObject);
     GameObject.Find ("FB_Login").gameObject.SetActive (false);

     Resources.UnloadUnusedAssets ();


     dict = Facebook.MiniJSON.Json.Deserialize (result.Text) as IDictionary;

     fbName = dict ["first_name"].ToString ();

     print ("The name is " + fbName );
 }

 void ProfilePicCallback(FBResult result)
 {
     if (result.Error != null && result.Texture == null) {
         Debug.LogWarning ("Problema al obtener la foto de perfil de facebook");
         FB.API (Util.GetPictureURL ("me", 128, 128), Facebook.HttpMethod.GET, ProfilePicCallback);
         return;
     } else {

 

         //Instantiate Canvas
         GameObject getPrefab = Resources.Load <GameObject> ("MyPrefabs/Facebook_Login_Canvas");
         loginCanvas = (GameObject)Instantiate (getPrefab, transform.position,transform.rotation);

         GameObject.Find ("FacebookPic").GetComponent<Image> ().sprite = Sprite.Create (result.Texture, new Rect (0, 0, 128, 128), new Vector2 (0.5f, 0.5f));
         Debug.Log ("Se creó el facebook Canvas");

         //Change Text to the username
         GameObject.Find ("FacebookPic").GetComponent<Image> ().sprite = Sprite.Create (result.Texture, new Rect (0, 0, 128, 128), new Vector2 (0.5f, 0.5f));
         GameObject.Find ("Greet").GetComponent<Text> ().text = "Hello " + fbName;
     }
 }

 }