通过AJAX发送电子邮件时出错500（Laravel 5.4）

我'm trying to have a form send emails in a Laravel project. However, I keep receiving 500 error. I' m关注this教程 .

这是路线：

Route::post('contact', 'PagesController@contact');

这是控制器：

public function contact(Request $request) {

    $this->validate($request, [
        'email'=>'required|email',
        'fullname'=>'max:50'
        ]);

    $data = array(
        'email' => $request->email,
        'fullname' => $request->fullname,
        );

    Mail::send('emails.contact', $data, function($message) use ($data){
        $message->from($data['email']);
        $message->to('moghrabi@gmail.com');

    });
}

这是包含带有CSRF的HTML表单的视图，如前面的问题所述 .

<form onsubmit="return false" method="post" id="contact_form" name="contact-form">

    <input type="hidden" name="_token" value="{{ csrf_field() }}">
    <input type="text" class="form-control" name="fullname" id="fullname" required>
    <input class="form-control" aria-describedby='sizing-addon1' placeholder="Email Address" required name="email" id="email">
    <button id="contact_btn" data-loading-text="Sending" >Send Your Message</button>

</form>

这是AJAX代码：

$('#contact_form').submit(function(e) {
              e.preventDefault();
            }).validate({ 

          rules: {
            fullname: {
              required: true,

            },
            email: {
              required: true,
              email: true
            },
         },
          submitHandler: function (form) {

            var btn = $('#contact_btn');
            btn.button('loading');
            setTimeout(function() {
              btn.button('reset');
            }, 8000);

            $.ajax({
              type: 'POST',
              url: "{{url('contact')}}",

              dataType: 'json',
              async: true,
              data: {

                fullname: $('#fullname').val(),
                email: $('#email').val(),

          },

              success: function (json) {
                $('#contact').hide();
                $('#output').html(
                  '<p>We have received your message!</p>'
                  ).show();
              }
            });
               return false; 
        } 
   });

在Chrome开发工具中：

无法加载资源：服务器响应状态为500（内部服务器错误）