PHPMailer提示邮件发送成功但收件人未收到问题求助（Godaddy环境）

我在GoDaddy购买了域名、主机和邮箱服务，使用PHPMailer实现网站邮件功能。PHPMailer显示邮件发送成功，但收件人始终未收到邮件。以下是我的PHP代码及PHPMailer调试日志，恳请各位提供解决建议：

PHP代码 #

<?php

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

require '/home/vv0srjz4gnsz/public_html/system/library/phpmailer/src/Exception.php';
require '/home/vv0srjz4gnsz/public_html/system/library/phpmailer/src/PHPMailer.php';
require '/home/vv0srjz4gnsz/public_html/system/library/phpmailer/src/SMTP.php';

$mail = new PHPMailer(true);  
$mail->isSMTP();
$mail->Host = 'localhost';
$mail->SMTPAuth = false;
$mail->SMTPAutoTLS = false; 
$mail->Port = 25; 
$mail->SMTPDebug = 3;
    
$mail->AddAddress('receiver@email.com', 'Receiver');
$mail->SetFrom('sender@email.com', 'Sender');
$mail->Subject = 'My Subject';
$mail->Body = 'Mail contents';
$mail->Username = 'auth@godaddyemaildomain.com'; 
$mail->Password = '!mypassword';

try{
    if ($mail->send()) {
      echo 'email sent success';
    } else {
      echo 'failed to send';
      echo $mail->ErrorInfo;
    }
} catch(Exception $e){
    //Something went bad
    echo "Fail - " . $mail->ErrorInfo;
}

?>

调试日志 #

2023-02-17 09:53:11 Connection: opening to localhost:25, timeout=300, options=array()
2023-02-17 09:53:11 Connection: opened
2023-02-17 09:53:11 SERVER -> CLIENT: 220-sg2plzcpnl453267.prod.sin2.secureserver.net ESMTP Exim 4.95 #2 Fri, 17 Feb 2023 02:53:11 -0700 220-We do not authorize the use of this system to transport unsolicited, 220 and/or bulk e-mail.
2023-02-17 09:53:11 CLIENT -> SERVER: EHLO www.godaddyDomain.com
2023-02-17 09:53:11 SERVER -> CLIENT: 250-sg2plzcpnl453267.prod.sin2.secureserver.net Hello www.godaddyDomain.com [127.0.0.1]250-SIZE 52428800250-8BITMIME250-PIPELINING250-PIPE_CONNECT250-AUTH PLAIN LOGIN250-STARTTLS250 HELP
2023-02-17 09:53:11 CLIENT -> SERVER: MAIL FROM:<sender@godaddyDomain.com>
2023-02-17 09:53:11 SERVER -> CLIENT: 250 OK
2023-02-17 09:53:11 CLIENT -> SERVER: RCPT TO:<receiver@godaddyDomain.com>
2023-02-17 09:53:11 SERVER -> CLIENT: 250 Accepted
2023-02-17 09:53:11 CLIENT -> SERVER: DATA
2023-02-17 09:53:11 SERVER -> CLIENT: 354 Enter message, ending with "." on a line by itself
2023-02-17 09:53:11 CLIENT -> SERVER: Date: Fri, 17 Feb 2023 09:53:11 +0000
2023-02-17 09:53:11 CLIENT -> SERVER: To: Mr Receiver <receiver@godaddyDomain.com>
2023-02-17 09:53:11 CLIENT -> SERVER: From: Mr Sender <sender@godaddyDomain.com>
2023-02-17 09:53:11 CLIENT -> SERVER: Subject: My Subject
2023-02-17 09:53:11 CLIENT -> SERVER: Message-ID: <muLYFVVw4LfUEMaV9Ot6WWxwnYHXYNs9UB1Mf0atZLU@www.godaddyDomain.com>
2023-02-17 09:53:11 CLIENT -> SERVER: X-Mailer: PHPMailer 6.1.7 (https://github.com/PHPMailer/PHPMailer)
2023-02-17 09:53:11 CLIENT -> SERVER: MIME-Version: 1.0
2023-02-17 09:53:11 CLIENT -> SERVER: Content-Type: text/plain; charset=iso-8859-1
2023-02-17 09:53:11 CLIENT -> SERVER:
2023-02-17 09:53:11 CLIENT -> SERVER: Mail contents
2023-02-17 09:53:11 CLIENT -> SERVER:
2023-02-17 09:53:11 CLIENT -> SERVER: .
2023-02-17 09:53:11 SERVER -> CLIENT: 250 OK id=1pSxQV-00HNWK-K8
2023-02-17 09:53:11 CLIENT -> SERVER: QUIT
2023-02-17 09:53:12 SERVER -> CLIENT: 221 sg2plzcpnl453267.prod.sin2.secureserver.net closing connection
2023-02-17 09:53:12 Connection: closed
email sent success

从日志看，邮件已经被GoDaddy的Exim服务器成功接收（返回250 OK id=1pSxQV-00HNWK-K8），问题出在后续投递或收件端过滤，按以下步骤排查：

• 优先检查垃圾邮件文件夹：自动发送的邮件大概率被收件邮箱归类到垃圾邮件、广告邮件或其他过滤文件夹，让收件人先确认这一点。
• 修正SMTP配置：
  • 当前代码开启了SMTPAuth=false，但又设置了Username和Password，逻辑矛盾。GoDaddy要求SMTP认证，且发件人地址需与认证账号一致。修改代码：

    $mail->SMTPAuth = true;
    $mail->SetFrom('auth@godaddyemaildomain.com', 'Sender'); // 和Username保持一致
    $mail->Host = 'smtpout.secureserver.net'; // 改用GoDaddy官方SMTP服务器，比localhost更可靠
    $mail->SMTPAutoTLS = true;
    $mail->Port = 587; // TLS端口，替代25端口（25常被拦截）
    

• 查看GoDaddy邮件投递日志：登录GoDaddy主机控制面板，找到Exim邮件日志，搜索邮件ID1pSxQV-00HNWK-K8，查看后续投递状态，确认是否存在退信、延迟或被收件方拒收的情况。
• 配置DNS认证记录：
  • 添加SPF记录，包含include:secureserver.net，允许GoDaddy服务器代表你的域名发送邮件；
  • 配置DKIM和DMARC记录，提升邮件可信度，降低被标记为垃圾邮件的概率。
• 测试同域名收件：先发送邮件到你GoDaddy域名下的邮箱（比如receiver@yourgodaddydomain.com），如果能收到，说明问题在外部收件邮箱的过滤规则；如果仍收不到，直接联系GoDaddy客服排查主机邮件服务问题。

内容的提问来源于stack exchange，提问作者Mike