Uncaught phpmailerException：无法实例化邮件功能

Question

[请确保我已经检查过所有此类可能的问题，然后才找到任何答案，并且看起来好像遇到了麻烦。我不是新开发人员。但是我没有php经验。我可以做基本的事情。如果对PHP和PHPMailer更有经验的人可以提供帮助，将非常感谢。

我有3个网站。他们大量使用联系表格。我一直在为所有人共享相同的php代码，并且一直在工作，直到昨天我发现邮件程序实际上没有发送邮件。

当我检查错误日志时。这是我发现的。

[05-Feb-2019 15:41:03 Africa/Johannesburg] PHP Fatal error:  Uncaught phpmailerException: Could not instantiate mail function. in /home/lovecharmking/public_html/phpmailer/class.phpmailer.php:1509
Stack trace:
#0 /home/lovecharmking/public_html/phpmailer/class.phpmailer.php(1346): PHPMailer->mailSend('Date: Tue, 5 Fe...', '<span><b>Name: ...')
#1 /home/lovecharmking/public_html/phpmailer/class.phpmailer.php(1215): PHPMailer->postSend()
#2 /home/lovecharmking/public_html/contact-form.php(47): PHPMailer->send()
#3 {main} thrown in/home/lovecharmking/public_html/phpmailer/class.phpmailer.php on line 1509.

这是我的代码。

<?php
ini_set('display_errors', '1');
require 'PHPMailerAutoload.php';

$contactEmail = $_POST['Email'];
$email2Spa = $_POST['Email2'];
$contactName = $_POST['Name'];
$contactNumber = $_POST['Cell'];
$reason = $_POST['Subject'];
$contactLocation = $_POST['Location'];
$contactMessage = $_POST['Message'];

if(!empty($email2Spa)) die();

$mail = new PHPMailer(true);

$mail->isSMTP();                             // Set mailer to use SMTP
$mail->SMTPDebug = 2;
$mail->SMTPKeepAlive = true;
$mail->Mailer = “smtp”; // don't change the quotes!
$mail->Host = 'mail.domainname.com';             // Specify main and backup SMTP servers
$mail->SMTPAuth = true;                     //  Enable SMTP authentication
$mail->Username = '[email protected]';          // SMTP username
$mail->Password = '**********'; // SMTP password 'TJ&ShBW[H*N#'
$mail->SMTPSecure = 'TLS';                  // Enable TLS encryption, `ssl` also accepted
$mail->Port = 587;                          // TCP port to connect to

$mail->setFrom('[email protected]', $contactName);
$mail->addAddress('[email protected]', 'Site Owner');     // Add a recipient
$mail->addReplyTo($contactEmail);
$mail->isHTML(true);  // Set email format to HTML

    $email_body = "";
    $email_body .= "<span><b>Name: </b> " . $contactName . "</span><br/><br/>";
    $email_body .= "<span><b>Reason: </b> " . $reason . "</span><br/><br/>";
    $email_body .= "<span><b>Email Address: </b>" . $contactEmail . "</span><br/>";
    $email_body .= "<p>Phone Number: " . $contactNumber . "</p>";
    $email_body .= "<p><b>Location: </b>" . $contactLocation . "</p>";
    $email_body .= "<p><b>Message: </b>" . $contactMessage . "</p>";

    // $mail->Priority = 1;
    $mail->AddCustomHeader("X-MSMail-Priority: High");
    $mail->AddCustomHeader("Importance: High");
    $mail->Subject = $reason;
    $mail->Body    = $email_body;

if(!$mail->send()) {
    // echo 'Mailer Error: ' . $mail->ErrorInfo;
    // $response = array('success'=>"successfully send", 'message'=>"Message sent.");;
   echo json_encode(array('success' => false, "Mailer Error: ".$mail->ErrorInfo));
} else {
  // return $data['success'] = true;
  // echo json_encode($data);
  // echo 'Message has been sent.';
  echo json_encode(array('success' => true, 'message' => "You message has been sent"));

}.

这里是Ajax调用：

$('#cform').submit(function(e){
  e.preventDefault();
  const formUrl = 'contact-form.php';
  let formData = $('#cform').serialize(); // Collect data from form
  $.ajax({
    type: "POST",
    url: formUrl,
    data: formData,
    timeout: 6000,
    error: function (request, error) {
      console.log(error);},
    success: function (data) {
      var response = JSON.parse(data);
      // console.log(response);
      if (response.success==true) {
        let alertDiv = document.createElement('div');
        alertDiv.innerHTML = `
        <strong>Your Message has been Sent!</strong> Admin will get back to you as soon as he is available.
        <button type="button" class="close" data-dismiss="alert" aria-label="Close">
        <span aria-hidden="true">&times;</span>
        </button>`
        $('.alert').alert();
        alertDiv.setAttribute('class','alert alert-warning alert-dismissible fade show alertBox');
        alertDiv.setAttribute('role','alert');
        // alertDiv.setAttribute('style','display:inline-block');
        let messageSpan = document.querySelector('.alertMessage');
        let parentForSpan = messageSpan.parentNode;
        parentForSpan.replaceChild(alertDiv,messageSpan);
        // contactForm.appendChild(alertDiv);
        $('#cform')[0].reset();
        // alertDiv.remove()
        // let span = document.createElement('span');
        // span.className = "alertMessage"
        // console.log(response);
      } else {
        console.log('Something wrong is going on. Check it.');
      }
      return false
    }});
    return false;
  });

这是ajax请求在浏览器中返回的内容：

Uncaught SyntaxError: Unexpected token C in JSON at position 1
    at JSON.parse (<anonymous>)
    at Object.success (main.js:212)
    at c (jquery.min.js:4)
    at Object.fireWith [as resolveWith] (jquery.min.js:4)
    at k (jquery.min.js:6)
    at XMLHttpRequest.r (jquery.min.js:6)

就像我说过的那样，我在三个站点之间共享代码，但是它们都无法正常工作。他们都已经运行了多年。任何输入将不胜感激。

Answer 1

这都是由此建议引起的：

$mail->Mailer = “smtp”; // don't change the quotes!

这完全是错误的。这些弯引号可能会导致Mailer设置为一些未定义的值，这意味着它将退回到使用mail()发送。无论如何，您不需要这样做，因为您先前对isSMTP()的调用正确设置了Mailer（假设您确实确实想使用SMTP），因此删除该行可能会有所帮助。

几乎与PHPMailer相关的所有答案都包含指向the troubleshooting guide的链接，该链接告诉您如何处理此错误：切换到SMTP或安装邮件服务器。它还会告诉您使用最新版本（不是），并将代码基于所提供的示例（而不是所使用的错误，过时，误导性的示例-我想知道您从何处获得了它。所以我可以请他们把它拆下来。

如果您是PHP新手（但不是编码人员），那么您应该做的第一件事是learn how to use composer; PHP的作曲者是ruby的宝石，npm是node的宝石，pip是python的宝石；用它来管理您的依赖项，例如PHPMailer。

[处理ajax处理程序时，请检查您的后端是否产生可理解的结果（例如，有效的JSON）之前您尝试通过JS使用它，因为将服务器端错误发送到客户端是很常见的（发生了什么事），通常无法从JS解析，然后您将遇到两个问题，而不是一个。