在localhost上，网站运行正常 . 但是当我上传到hosting =>它返回HTTP错误500（内部服务器错误）

如果我在库上调用不可用库或调用不可用函数（它不会返回任何错误，只是空白页），结果相同

例：

class My_Email extends CI_Email{
    public function sz_send($to,$bcc,$subject,$content)
    {
        $CI =& get_instance();
        // get config
        $CI->load->model('config_model');
        $site_config = $CI->config_model->getconfig();
        // init mail

        $mail_config['protocol'] = 'smtp';
        $mail_config['smtp_host'] = $site_config['mail_host'];
        $mail_config['smtp_port'] = $site_config['mail_port'];
        $mail_config['smtp_user'] = $site_config['mail_user'];
        $mail_config['smtp_pass'] = $site_config['mail_pass'];
        $mail_config['charset'] = 'utf-8';
        $mail_config['mailtype'] = 'html';
        $mail_config['wordwrap'] = TRUE;
        $mail_config['smtp_timeout'] = '7';
        $mail_config['newline']    = "\r\n";
        $mail_config['validation'] = TRUE;
        $CI->load->library('email');
        $CI->email->initialize($mail_config);
        $CI->email->from($site_config['mail_user'], $site_config['mail_name']);
        $CI->email->to($to);
        $CI->email->bcc($bcc);
        $CI->email->subject($subject);
        $CI->email->message($content);
        if($CI->email->send()){
            return TRUE; 
        } else {
            //echo $CI->email->print_debugger();
            return FALSE;
        }
    }
}

在控制器中，我打电话给：

$this->load->library('email');
$this->email->sz_send($user->email,'','Subject',$mailcontent);

网站返回时带有FF的空白页和带有Chorme的HTTP错误500（内部服务器错误）

p / s：我如何在托管（linux）上看到apache日志文件？

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