Mail（）BCC - 无法让它工作

I'm having a bit of trouble creating a mail function that sends form result - some calculations - to the user. It was working fine until I added a bcc header and now no email gets sent.

The pertinent code is below and the page can be seen here: http://benefacto.org/calculator/

This is my first major php project!

Here is my mail function:

if($_POST["submit1"]) {
    $recipient=$_POST["email"] . ",example@example.org";
    $subject="Volunteering Costs at $companyname";
    $sender=$_POST["sender"];
    $senderEmail="example@example.org";
    $message=round($recturnoverdcrease,3) . "%";
    $message1=$_POST["companyname"];
    $message2=round($totalcost,2);
    $message3=round($increaserec,3) . "%";
    $themodel='http://benefacto.org/wp-content/uploads/BNFO_CostCalculator_BD_v1.0_160127.xlsx';
    $headers='Bcc: other@example.com' . "
";

    // Email Message
    $mailBody="Volunteering at $message1


        Outputs: 



        Productivity Gain Needed Amongst staff to cover cost: $message3 

        Decrease in Staff Turnover Required to Offset Cost:$message 

        Total Cost £$message2 


        Inputs: 



        Your Company's UK Headcount: $valuea

        Average Salary at your Company: $value 

        Your Company's UK Operating Profit: $valueb

        Brokerage Costs: $valuec

        Anticipated Uptake: $valued


        Download the model here: $themodel 


        ";

    mail($recipient, $subject, $mailBody, "From: $sender <$senderEmail>", $headers);
}

If you look at the docs (http://php.net/manual/de/function.mail.php), mail accepts headers as the 4th parameter. Your 4th parameter is the "From"-line. The fifth parameter is passed to the mail binary (sendmail or whatever, generally you don't need to mess with it).

You need to append the BCC line to the FROM line (both are headers). Try this:

$headers  = "From: $sender <$senderEmail>
"
$headers .= "Bcc: other@example.com
";

// ...

mail($recipient, $subject, $mailBody, $headers);