node.js - ldapjs - write after end error -

i have created authentication service using following code in node.js , ldapjs.

var when = require ('when'); var authenticationerror = require('../errors/authenticationerror'); var sessionmanagerservice = require('./sessionmanagerservice');  var ldap = require('ldapjs');  var client = ldap.createclient({     url: 'ldaps://ad.mycompany.com:636',     tlsoptions: {'rejectunauthorized': false} });  module.exports = {      signin: function (email, password) {         return this.ldapbind(email, password).then(             function () {                 return sessionmanagerservice.createsessionhash({email: email});             }         );     },      ldapbind: function (email, password) {         var deferred = when.defer();         client.bind(email, password, function(err) {             if (err) {                 deferred.reject (new authenticationerror('invalid username and/or password!', 'authentication.signin.error'));             } else {                 client.unbind();                 deferred.resolve(true);             }         });         return deferred.promise;     },  }; 

when authenticate user first time, works fails starting second attempt. error message is: 'write after end'.

when restart node server works again first attempt.

it looks hanging don't know what. idea?

i solved problem few days ago creating ldap-client every time in ldapbind function (in case).