Codeigniter：Ajax电子邮件检查错误500

Question

您好我通过ajax检查电子邮件问题，它总是让我得到内部错误500

edituser.php：

<form class="fcms" name="fcms" action="<?php echo base_url(); ?>cuser/newUser" method="POST" role="form">
    <div class="row">
        <div class="col-lg-2 col-md-2 col-sm-2 col-xs-12">
            <label><strong>Email: *</strong></label>
        </div>
        <div class="col-lg-4 col-md-4 col-sm-4 col-xs-12">
            <input type="email" name="email" id="email" value="" required />
            <span id="email_result"></span> 
        </div>
    </div>
    <div class="row">
        <div class="col-lg-12 col-md-12 col-sm-12 col-xs-12">
            <button type="submit" name="boton" onClick="javascript:Validar();">Registrer</button>
        </div>
    </div>
</form>
<script>
    var baseurl = "<?php echo base_url(); ?>";

    $(document).ready(function(){
        $('#email').change(function(){
            var email = $('#email').val();
            if(email != '')
            {
                $.ajax({
                    url:baseurl+"cuser/email_check", // here goes to the controller
                    method:"POST",
                    data:{email:email},
                    success:function(data){
                        if(data.status=="success"){
                            $('#email_result').html(data);
                        }else{
                            console.log(data)
                        }
                    }
                });
            }
        });
    });
</script>

控制器：cuser

public function email_check(){
    if(!filter_val($_POST["email"], FILTER_VALIDATE_EMAIL)){
        echo 'Invalid Email';
    }else{
        $this->load->model('muser');
        if($this->muser->is_email_available($_POST["email"])){  
            echo 'Email Already register';
        }else{  
            echo 'Email Available';  
        }
    }
}

型号：muser

public function is_email_available($email){  
    $this->db->where('email', $email);
    $query = $this->db->get("admin"); // database
    if($query->num_rows() > 0){
       return true;
    }else{
        return false;
    }
}

检查电子邮件时，控制台日志会返回错误： POST http://localhost/webs/admin/cuser/email_check 500（内部服务器错误）

感谢。