cant send mail

[byg-e]

Hey

Im having problems sending mails from SupportSuite. I discovered the problem, when i made a test user and no activation mail was send. Then i tried to make a small php script which sends a simple mail:

PHP Code:

<?php
$to = "test@msn.com";
$subject = "Test af mail sendning";
$message = "Jaaah, dette er så en test.";
$headers = "From: test@toyou.com";
echo "<h2>This sends mail to ".$to."</h2>";
if(mail($to, $subject, $message, $headers)){
    echo "Send!";
}else{
    echo "Could'nt send the mail :(";
}
?>

And it unfortunally shows: "Couldnt send the mail ".

What could be wrong? I havent set any smtp.