In what situations would it be beneficial to debug the SMTP connection using the SMTP-Debug mode when dealing with PHP mail() function issues?

When dealing with PHP mail() function issues, it would be beneficial to debug the SMTP connection using the SMTP-Debug mode if you are facing problems with sending emails, such as emails not being delivered or errors being returned. By enabling SMTP-Debug mode, you can view detailed information about the SMTP communication process, which can help you identify and troubleshoot any issues with the email sending process.

// Enable SMTP debugging
ini_set('smtp_debug', '1');

// Send email using PHP mail() function
$to = 'recipient@example.com';
$subject = 'Test Email';
$message = 'This is a test email.';
$headers = 'From: sender@example.com';

$mail_sent = mail($to, $subject, $message, $headers);

if ($mail_sent) {
    echo 'Email sent successfully.';
} else {
    echo 'Failed to send email.';
}