使用 facebook javascript SDK 登录时无法获取公共用户电子邮件

在这里，我正在使用facebook它进行登录工作正常，但我无法获得登录用户email，当时只有公共用户登录我无法收到电子邮件，但我收到了name，我不知道我在哪里做错了就像我的代码或仪表板控制台

<input type="button" class="btn btn-lg btn-fb" value="Sign in using Facebook" onclick="checkFacebookLogin();"/>


<script>

  window.fbAsyncInit = function() {
      FB.init({appId: '1990039811315283', status: true, cookie: true, xfbml: true});

  };
  (function() {
    var e = document.createElement('script'); e.async = true;
    e.src = document.location.protocol +
      '//connect.facebook.net/en_US/all.js';
    document.getElementById('fb-root').appendChild(e);
  }());

function fetchUserDetail()
{
    FB.api('/me', {fields: 'name,email'}, function(response) {
            //console.log("Name: "+ response.name + "\Email: "+ response.email + "ID: "+response.id);
            var userName = response.name;
            var userEmail = response.email;
            var profilePic = '1.png';
            var registerFrom = 'Web';
            var FCM_Token = '';
              $.ajax({
                url:'admin/rest/registerFB',
                type:'POST',
                data: {userName: userName, userEmail: userEmail, profilePic: profilePic, registerFrom: registerFrom, FCM_Token: FCM_Token},
                success:function(loginResponse){
                      if(loginResponse['status']=='success'){
                          window.location.href = "index.php";
                      } 

                },
            }); 
        });
}

function checkFacebookLogin() 
{
    FB.getLoginStatus(function(response) {
      if (response.status === 'connected') {
        fetchUserDetail();
      } 
      else 
      {
        initiateFBLogin();
      }
     });
}

function initiateFBLogin()
{
    FB.login(function(response) {
       fetchUserDetail();
     });
}
</script>

我收到类似 undefinedID 的错误