Problem sharing a screenshot in IOS

The code below works perfect in Android but in IOS i get this error:

"EntryPointNotFoundException: showSocialSharing ScreenShotShare.CallSocialShareAdvanced (System.String defaultTxt, System.String subject, System.String url, System.String img) (at Assets/ScreenShotShare.cs:107) ScreenShotShare+c__Iterator0.MoveNext () (at Assets/ScreenShotShare.cs:115) UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) (at /Users/builduser/buildslave/unity/build/Runtime/Export/Coroutines.cs:17)"

This is the script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using System.IO;
 using System.Runtime.InteropServices;
 
 public class ScreenShotShare : MonoBehaviour
 {
 
     public string subject, ShareMessage, url;
     private bool isProcessing = false;
     public string ScreenshotName = "DenysScreenshot.png";
 
     public void ShareScreenshotWithText()
     {
         // Share();
 
     }
 
     public void Share()
     {
 #if UNITY_ANDROID
         if (!isProcessing)
             StartCoroutine(ShareScreenshot());
 #elif UNITY_IOS
  if(!isProcessing)
  StartCoroutine( CallSocialShareRoutine() );
 #else
  Debug.Log("No sharing set up for this platform.");
 #endif
     }
 #if UNITY_ANDROID
     public IEnumerator ShareScreenshot()
     {
         isProcessing = true;
 
         // wait for graphics to render
         yield return new WaitForEndOfFrame();
         string screenShotPath = Application.persistentDataPath + "/" + ScreenshotName;
         Application.CaptureScreenshot(ScreenshotName);
 
 
 
         yield return new WaitForSeconds(1f);
         if (!Application.isEditor)
         {
 
 
             AndroidJavaClass intentClass = new AndroidJavaClass("android.content.Intent");
             AndroidJavaObject intentObject = new AndroidJavaObject("android.content.Intent");
 
             intentObject.Call<AndroidJavaObject>("setAction", intentClass.GetStatic<string>("ACTION_SEND"));
             AndroidJavaClass uriClass = new AndroidJavaClass("android.net.Uri");
             AndroidJavaObject uriObject = uriClass.CallStatic<AndroidJavaObject>("parse", "file://" + screenShotPath);
             intentObject.Call<AndroidJavaObject>("putExtra", intentClass.GetStatic<string>("EXTRA_STREAM"), uriObject);
             intentObject.Call<AndroidJavaObject>("setType", "image/png");
 
             intentObject.Call<AndroidJavaObject>("putExtra", intentClass.GetStatic<string>("EXTRA_TEXT"), ShareMessage);
 
             AndroidJavaClass unity = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
             AndroidJavaObject currentActivity = unity.GetStatic<AndroidJavaObject>("currentActivity");
 
             AndroidJavaObject jChooser = intentClass.CallStatic<AndroidJavaObject>("createChooser", intentObject, "Share Picture");
             currentActivity.Call("startActivity", jChooser);
 
         }
         isProcessing = false;
     }
 #endif
 #if UNITY_IOS
  public struct ConfigStruct
  {
  public string title;
  public string message;
  }
  
  [DllImport ("__Internal")] private static extern void showAlertMessage(ref ConfigStruct conf);
  
  public struct SocialSharingStruct
  {
  public string text;
  public string url;
  public string image;
  public string subject;
  }
  
  [DllImport ("__Internal")] private static extern void showSocialSharing(ref SocialSharingStruct conf);
  
  public void CallSocialShare(string title, string message)
  {
  ConfigStruct conf = new ConfigStruct();
  conf.title = title;
  conf.message = message;
  showAlertMessage(ref conf);
  isProcessing = false;
  }
  
  public static void CallSocialShareAdvanced(string defaultTxt, string subject, string url, string img)
  {
  SocialSharingStruct conf = new SocialSharingStruct();
  conf.text = defaultTxt; 
  conf.url = url;
  conf.image = img;
  conf.subject = subject;
  
  showSocialSharing(ref conf);
  }
  IEnumerator CallSocialShareRoutine()
  {
  isProcessing = true;
  string screenShotPath = Application.persistentDataPath + "/" + ScreenshotName;
  Application.CaptureScreenshot(ScreenshotName);
  yield return new WaitForSeconds(1f);
  CallSocialShareAdvanced(ShareMessage, subject, url, screenShotPath);
 
  }
 
 #endif
 }