Not detecting drop event

I'm doing a game in unity3d, and I need to drag and drop text components over other text components.

I have a canvas with a canvas group. Inside there are two panels with a Grid Layout Group. I'm loading programatically a component (prefab) consisting in a Panel and a Text, and then I'm adding it to his parent. I have 2 scripts, a ItemDragHandler and TextDropHandler, after adding these two handlers to my prefab, I get that the ItemDropHandler is never executing the OnDrop function. I have used these two scripts before and they have worked. I already disable the raycasts in my canvas group also programatically. I don't know what can be wrong because it already worked with an Image component.

 public class TextDropHandler: MonoBehaviour, IDropHandler
 {
     public void OnDrop(PointerEventData eventData)
     {
         Debug.Log("Drop detectado"); //never shown in the Unity Debug
         Texto txtDrag = ItemDragHandler.startParent.gameObject.GetComponent<SlotText>().texto;
         Texto txtDrop = transform.gameObject.GetComponentInParent<SlotText>().texto;
 
         DropTextTextContainer dttc = GetComponentInParent<DropTextTextContainer>();
         if (dttc.verify(txtDrag, txtDrop) && !dttc.showNextText())
         {
             //Destroy(transform.parent.gameObject);
             ItemDragHandler.destroyObject = true;     
         }
     }
 }
 public class ItemDragHandler : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
 {
     public static GameObject itemBeingDragged;
     public static Transform startParent;
 
 
     public static bool destroyObject;
 
     Vector3 startPosition;
 
 
     public void OnBeginDrag(PointerEventData eventData)
     {
         Debug.Log("Drag ha comenzado");
         itemBeingDragged = gameObject;
         startPosition = transform.position;
         startParent = transform.parent;
         GetComponentInParent<CanvasGroup>().blocksRaycasts = false;
     }
 
     public void OnDrag(PointerEventData eventData)
     {
         transform.position = Input.mousePosition;
     }
 
     public void OnEndDrag(PointerEventData eventData)
     {
         Debug.Log("Drag finalizado");
 
         if (destroyObject)
         {
             Destroy(startParent.gameObject);
             destroyObject = false;
         }
         itemBeingDragged = null;
         startParent = null;
         if(transform.parent != startParent) { 
         transform.position = startPosition;
         }
 
         GetComponentInParent<CanvasGroup>().blocksRaycasts = true;
     }
 }

I expect the drop function to be executed when I drag an object into the other.