Kirupa Contact Form PHP not working (sending to Yahoo)

Hi,

I have setup up the contact form and mailer.php script, however when i submit the contact form and set the $to = to a yahoo email i do not receive any emails.

When i set it to info@mydomainname.co.uk it works?

Seems like its not working for some emails?

Can anyone help or know why i cant receive them?

HTML

<form id="sendemail" method="post" action="mailer.php">             <ol>              <li>                <label for="name">Name (required)</label>                <input type="text" name="name" class="validate[required] text" id="name" />              </li>              <li>                <label for="email">Email Address (required)</label>                <input type="text" name="email" class="validate[required,custom[email]] text"  id="email"  />              </li>              <li>                <label for="subject">Subject</label>                <input type="text" name="subject" id="subject" class="text" />              </li>              <li>                <label for="message">Your Message</label>                <textarea value="" class="validate[required,length[6,1000]] message" name="message" id="message" rows="8" cols="50" /> </textarea>              </li>              <li>                <input type="image" value="Submit" name="submit" id="imageField" src="images/submit.gif" class="submit" />                <div class="clr"></div>              </li>            </ol>          </form>

PHP MAILER SCRIPT

<?PHP $to = "name@isp.co.uk"; $subject = "Results from your Request Info form";$headers = "From: warrington-kitchen-installations.co.uk";$forward = 1;$location = "thank-you.html";
$date = date ("l, F jS, Y"); $time = date ("h:i A"); 


$msg = "Below is the result of your feedback form. It was submitted on $date at $time.

"; 
if ($_SERVER['REQUEST_METHOD'] == "POST") {    foreach ($_POST as $key => $value) {         $msg .= ucfirst ($key) ." : ". $value . "
";     }}else {    foreach ($_GET as $key => $value) {         $msg .= ucfirst ($key) ." : ". $value . "
";     }}
mail($to, $subject, $msg, $headers); if ($forward == 1) {     header ("Location:$location"); } else {     echo "Thank you for submitting our form. We will get back to you as soon as possible."; } 
?>

Thanks
Paul