An Office365 SMTP Fix for PHPMailer Error 500 Guide

How to Fix PHPMailer Error 500 Using Office365 SMTP Settings

Utilizing PHPMailer Library with PHP

// Frontend Form (HTML)
<form action="send_email.php" method="post">
  <label for="name">Name:</label>
  <input type="text" id="name" name="name" required>
  <label for="email">Email:</label>
  <input type="email" id="email" name="email" required>
  <label for="message">Message:</label>
  <textarea id="message" name="message" required></textarea>
  <button type="submit">Send</button>
</form>

Using PHPMailer to Send Emails with Office365 SMTP

PHP Backend Script

<?php
use PHPMailer\\PHPMailer\\PHPMailer;
use PHPMailer\\PHPMailer\\Exception;
require 'vendor/autoload.php';

$mail = new PHPMailer(true);
try {
    // Server settings
    $mail->isSMTP();
    $mail->Host = 'smtp.office365.com';
    $mail->SMTPAuth = true;
    $mail->Username = 'your-email@domain.com'; // Your email address
    $mail->Password = 'your-email-password'; // Your email password
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port = 587;

    // Recipients
    $mail->setFrom('no-reply@domain.com', 'Company Name');
    $mail->addAddress('recipient@domain.com', 'Recipient Name');

    // Content
    $mail->isHTML(true);
    $mail->Subject = 'New message from ' . $_POST['name'];
    $mail->Body    = $_POST['message'];
    $mail->AltBody = strip_tags($_POST['message']);

    $mail->send();
    echo 'Message has been sent';
} catch (Exception $e) {
    echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";
}
?>

Ensuring Proper PHPMailer Configuration

PHP Configuration Settings

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

// Enable TLS 1.2 explicitly if required by the server
stream_context_set_default(
    array('ssl' => array(
        'crypto_method' => STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
    ))
);

Frequently Asked Questions and Answers for PHPMailer with Office 365

1. What port is ideal for SMTP access to Office 365?
2. For SMTP with STARTTLS, Office365 normally utilizes port 587; however, depending on your server configuration, you may also use ports $mail->isHTML(true) and 465.
3. Must I log in using my Microsoft account details?
4. No, you ought to send emails using the password and email address associated with the account you wish to utilize.
5. In my code, how can I enforce TLS version 1.2?
6. By using stream_context_set_default with the necessary settings, you can enforce TLS 1.2.
7. Why does sending emails result in an error 500?
8. Incorrect server configuration, including the use of the wrong port, invalid credentials, or altered security settings, might result in Error 500.
9. In PHPMailer, how do I set the SMTP server?
10. To specify the SMTP server, for example, $mail->Host = 'smtp.office365.com', use the $mail->Host property.
11. What does $mail->SMTPAuth want to achieve?
12. Sending emails with Office365 requires SMTP authentication, which is enabled by the $mail->SMTPAuth attribute.
13. How can I change the email address that is sent?
14. The email address and name of the sender should be specified using the $mail->setFrom technique.
15. Is it possible to add more than one recipient?
16. Yes, you are able to add many recipients using the $mail->addAddress technique.
17. How can I configure HTML as the email format?
18. To set the email format to HTML, use the $mail->isHTML(true) technique.

Completing Office365 PHPMailer Configuration

Make sure your server configurations are right when using PHPMailer with Office365 SMTP to prevent error 500. This entails supplying the proper credentials, configuring the proper encryption mechanism, and utilizing the proper port. You can send emails successfully and error-free if you closely follow the setup instructions and troubleshooting guides. Maintaining secure and seamless email communication will be made easier by routinely checking these configurations.