What are some best practices for troubleshooting email delivery issues in PHP scripts?

Issue: When sending emails from PHP scripts, sometimes the emails do not get delivered to the recipients' inbox due to various reasons such as misconfigured SMTP settings, spam filters blocking the email, or incorrect email headers. Solution: To troubleshoot email delivery issues in PHP scripts, ensure that the SMTP settings are correctly configured, check for any errors in the email headers, and test sending emails to different email addresses to identify the root cause of the problem. PHP Code Snippet:

// Example PHP script to send an email using PHP's mail() function
$to = "recipient@example.com";
$subject = "Test Email";
$message = "This is a test email sent from PHP script.";
$headers = "From: sender@example.com\r\n";
$headers .= "Reply-To: sender@example.com\r\n";
$headers .= "X-Mailer: PHP/" . phpversion();

if (mail($to, $subject, $message, $headers)) {
    echo "Email sent successfully.";
} else {
    echo "Email delivery failed.";
}