php mail script not sending mail [duplicate]

When I use the script below, no message gets sent. The failure message also doesn’t appear. I just get a blank screen. If I remove the $_POST, everything works. I double-checked the name of the form element coming over from the other page, so there is no typo there. I also noticed that the message fails if I add a variable for the mail header (but I do get the failure message in the else statemnt for that one…)

Thanks in advance!

<?php
    $to = "[email protected]";
    $subject = "Test Email from PHP";
    $message = "This is a test email sent using the PHP mail() function. From: " 
    $from = $_POST['subAdd'];
    $message = $message . $from

    if (mail($to, $subject, $message)){
      header("Location: http://practice.bkjdesignspa.com");
    }
    else{
      echo "Message failed";
    }

?>