问邮件功能不在联机服务器上工作

EN

$to = "info@domain.com";
    $subject = "Account request from $first_name $last_name";
    $emailBody = "
            hi,
            <br /><br />
            <strong>First Name</strong> : $first_name.<br />
            <strong>Last Name</strong> : $last_name.<br />
            <strong>Phone</strong> : $phone.<br />
            <strong>Email</strong> : $email.<br />
            <strong>Message</strong> : $message.
    ";

    //  Email headers
    $headers = "MIME-Version: 1.0" . "\r\n";
    $headers .= "Content-type:text/html;charset=iso-8859-1" . "\r\n";
    $headers .= 'From: domain' . "\r\n";

    //  Email Function
    $mail = mail($to,$subject,$emailBody,$headers);

if($mail)
{
echo 'success';
}
else
{
echo 'fail';
}