How can one troubleshoot and resolve connection timeout issues when trying to send emails to T-Online addresses using PHP?

Connection timeout issues when sending emails to T-Online addresses using PHP can be resolved by adjusting the timeout settings in the PHP mail function. You can increase the timeout value to allow more time for the connection to be established with the T-Online mail server. Additionally, make sure that the T-Online server is reachable and not blocking connections from your server.

// Set the timeout value for the mail function
ini_set('max_execution_time', 300); // 5 minutes

// Send email to T-Online address
$to = 'recipient@t-online.de';
$subject = 'Test Email';
$message = 'This is a test email';
$headers = 'From: your_email@example.com';

if (mail($to, $subject, $message, $headers)) {
    echo 'Email sent successfully';
} else {
    echo 'Failed to send email';
}