PHP: I cant send an email to multiple recipients - php

Question

I've checked php manual, but still can't get my script to work
If I delete the BCC line, the mail goes to $to1 but with BCC line, it goes nowhere
here is the code:
// email stuff
$to1 = "address1#mail.com";
$to2 = "address2#mail.com";
$from = "noreply#mail.com";
$subject = "Subject";
$message = "message";
// a random hash will be necessary to send mixed content
$separator = md5(time());
// carriage return type (we use a PHP end of line constant)
$eol = PHP_EOL;
// main header
$headers = "To: ".$to1.$eol;
$headers .= "From: ".$from.$eol;
$headers .= "Bcc: ".$to2.$eol;
$headers .= "MIME-Version: 1.0".$eol;
$headers .= "Content-Type: multipart/mixed; boundary=\"".$separator."\"".$eol;
// no more headers after this, we start the body! //
$body = "--".$separator.$eol;
$body .= "Content-Transfer-Encoding: 7bit".$eol;
$body .= "This is a MIME encoded message.".$eol;
// message
$body .= "--".$separator.$eol;
$body .= "Content-Type: text/html; charset=\"iso-8859-1\"".$eol;
$body .= "Content-Transfer-Encoding: 8bit".$eol;
$body .= $message.$eol;
// send message
mail($to1, $subject, $body, $headers);
If anyone has an idea, thanks a lot