What is the significance of the error "Client was not authenticated" in PHP mail functions?

The error "Client was not authenticated" in PHP mail functions typically occurs when the SMTP server requires authentication before sending emails. To solve this issue, you need to provide the correct SMTP authentication details in your PHP code. 

// Set SMTP server settings
$smtp_server = 'your_smtp_server';
$smtp_username = 'your_smtp_username';
$smtp_password = 'your_smtp_password';
$smtp_port = 587; // or the appropriate port for your SMTP server

// Set up PHPMailer
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

require 'vendor/autoload.php';

$mail = new PHPMailer(true);
$mail->isSMTP();
$mail->Host = $smtp_server;
$mail->SMTPAuth = true;
$mail->Username = $smtp_username;
$mail->Password = $smtp_password;
$mail->SMTPSecure = 'tls';
$mail->Port = $smtp_port;

// Add your email sending code here

Keywords

PHP mail functions error message authentication client

Related Questions