Authentification LDAP avec un compte de service en Java

J'essaie d'authentifier les utilisateurs de LDAP avec un compte de service créé. Je reçois une erreur ci-dessous sur ctx = new InitialDirContext(env);

[LDAP: code d'erreur 49-8009030C: LdapErr: DSID-0C0903A8, commentaire: erreur AcceptSecurityContext, données 2030, v1db1

quelqu'un Peut-il m'aider à comprendre où vais-je tort ?

Ceci est mon fichier java

/**
 * 
 */
package com.dei;

import java.util.Hashtable;

import javax.naming.AuthenticationException;
import javax.naming.Context;
import javax.naming.NameNotFoundException;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.SizeLimitExceededException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;
import javax.naming.directory.SearchControls;
import javax.naming.directory.SearchResult;

public class LdapConnector {


        private static final String LDAP_SERVER_PORT = "389";
        private static final String LDAP_SERVER = "server";
        private static final String LDAP_BASE_DN = "OU=role,OU=roles,OU=de,OU=apps,DC=meta,DC=company,DC=com";
        private static final String LDAP_BIND_DN = "cn=service_account";//service account userid provided by LDAP team
        private static final String LDAP_BIND_PASSWORD = "password";///service account pwd provided by LDAP team


        public Boolean validateLogin(String userName, String userPassword) {
            Hashtable<String, String> env = new Hashtable<String, String>();
            env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
            env.put(Context.PROVIDER_URL, "ldap://" + LDAP_SERVER + ":" + LDAP_SERVER_PORT + "/" + LDAP_BASE_DN);

            // To get rid of the PartialResultException when using Active Directory
            env.put(Context.REFERRAL, "follow");

            // Needed for the Bind (User Authorized to Query the LDAP server) 
            env.put(Context.SECURITY_AUTHENTICATION, "simple");
            env.put(Context.SECURITY_PRINCIPAL, LDAP_BIND_DN);
            env.put(Context.SECURITY_CREDENTIALS, LDAP_BIND_PASSWORD);

            DirContext ctx;
            try {
               ctx = new InitialDirContext(env);
            } catch (NamingException e) {
               throw new RuntimeException(e);
            }

            NamingEnumeration<SearchResult> results = null;

            try {
               SearchControls controls = new SearchControls();
               controls.setSearchScope(SearchControls.SUBTREE_SCOPE); // Search Entire Subtree
               controls.setCountLimit(1);   //Sets the maximum number of entries to be returned as a result of the search
               controls.setTimeLimit(5000); // Sets the time limit of these SearchControls in milliseconds

               String searchString = "(&(objectCategory=user)(sAMAccountName=" + userName + "))";

               results = ctx.search("", searchString, controls);

               if (results.hasMore()) {

                   SearchResult result = (SearchResult) results.next();
                   Attributes attrs = result.getAttributes();
                   Attribute dnAttr = attrs.get("distinguishedName");
                   String dn = (String) dnAttr.get();

                   // User Exists, Validate the Password

                   env.put(Context.SECURITY_PRINCIPAL, dn);
                   env.put(Context.SECURITY_CREDENTIALS, userPassword);

                   new InitialDirContext(env); // Exception will be thrown on Invalid case
                   System.out.println("Login successful");
                   return true;
               } 
               else 
                   return false;

            } catch (AuthenticationException e) { // Invalid Login
                System.out.println("Login failed" +e.getMessage());

                return false;
            } catch (NameNotFoundException e) { // The base context was not found.
                System.out.println("Login failed" +e.getMessage());
                return false;
            } catch (SizeLimitExceededException e) {
                throw new RuntimeException("LDAP Query Limit Exceeded, adjust the query to bring back less records", e);
            } catch (NamingException e) {
               throw new RuntimeException(e);
            } finally {

               if (results != null) {
                  try { results.close(); } catch (Exception e) { /* Do Nothing */ }
               }

               if (ctx != null) {
                  try { ctx.close(); } catch (Exception e) { /* Do Nothing */ }
               }
            }
        }
}