What potential issues can arise from not setting a variable return path in PHP mail forms?

Without setting a variable return path in PHP mail forms, emails sent from the form may be marked as spam or not delivered at all. To solve this issue, you can set the return path using the fifth parameter of the mail() function in PHP. 

$to = "recipient@example.com";
$subject = "Subject";
$message = "Message";
$headers = "From: sender@example.com\r\n";
$return_path = "-f return@example.com";

mail($to, $subject, $message, $headers, $return_path);

Keywords

PHP mail forms return path email headers deliverability

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