代码点火器:SMTP 邮件不起作用

我正在尝试设置一个联系表单，但我正在努力让它与 CI 中的 SMTP 配置一起工作。但是，我已经成功地尝试了基本的"邮件"配置。

简而言之，我正在使用以下简单代码进行测试：

    $config = array(
        'protocol' => 'smtp',
        'smtp_host' => 'smtp.1and1.es',
        'smtp_port' => 25,
        'smtp_user' => 'user@mysite.com', 
        'smtp_pass' => '********',
        'mailtype'  => 'text',
        'charset'   => 'utf-8',
        'wordwrap'  => true,
        'wrapchars' => 50            
    );
    $this->load->library('email');
    $this->email->initialize($config);
    $this->email->from('my_real_email_address@gmail.com');
    $this->email->to('my_real_email_address@gmail.com');
    $this->email->reply_to('my_real_email_address@gmail.com', 'John Doe');
    $this->email->subject('Message sent from the contact form in website');
    $this->email->message('Body of message...');
    if ($this->email->send()) {
            return true;
    }
    echo '<!--' . print_r($this->email->print_debugger(), true) . '-->'; 
    return false;

我刚刚问了我的托管服务提供商，所有SMTP配置都是正确的。他们还检查了我的电子邮件帐户是否正常工作。

事实上，如果我选择：

协议 => "邮件"

消息传递没有问题。AFAIK php mail（） 函数也使用托管提供程序 SMTP，但它只是将其交给服务器并忘记它。

相反，我想使用SMTP身份验证，这担心电子邮件的发送。但只有通过改变

协议 => "SMTP"

当我发送表单时，有很多处理时间，我终于收到以下调试消息：

220 smtp.1and1.es (mreu2) Welcome to Nemesis ESMTP server
hello:  The following SMTP error was encountered:
Failed to send AUTH LOGIN command. Error: 421 smtp.1and1.es connection timed out
from:  The following SMTP error was encountered:
to:  The following SMTP error was encountered: 
data:  The following SMTP error was encountered:  
The following SMTP error was encountered: 
Unable to send email using PHP SMTP.  Your server might not be configured to send mail using this method.
User-Agent: CodeIgniter
Date: Thu, 24 Jan 2013 18:51:31 +0100
From: <my_real_email_address@gmail.com>
Return-Path: <my_real_email_address@gmail.com>
To: my_real_email_address@gmail.com
Reply-To: "John Doe" <my_real_email_address@gmail.com>
Subject: =?utf-8?Q?Message_sent_from_the_contact_form_in_website?=
X-Sender: my_real_email_address@gmail.com
X-Mailer: CodeIgniter
X-Priority: 3 (Normal)
Message-ID: <510174a33158d@gmail.com>
Mime-Version: 1.0

Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Body of message...

此错误的原因可能是什么？