I am using the following to attach a .docx file to my email to send out. The issue is, nothing gets sent. Here is what I am doing:
    $uid = md5(uniqid(time()));
    $header = "From: ....";
    $header .= "MIME-Version: 1.0\r\n";
    $header .= "Content-type:text/html; charset=iso-8859-1\r\n";
    $header .= "Content-Transfer-Encoding: 7bit\r\n\r\n"; 
    $filename = "test";
    $file = getcwd() . "/attachments/test.docx";
    $name = basename($file);
    $file_size = filesize($file);
    $handle = fopen($file, "r");
    $content = fread($handle, $file_size);
    fclose($handle);
    $content = chunk_split(base64_encode($content));
    $header .= "--".$uid."\r\n";
    $header .= "Content-Type: application/octet-stream; name=\"".$filename."\"\r\n"; // use different content types here
    $header .= "Content-Transfer-Encoding: base64\r\n";
    $header .= "Content-Disposition: attachment; filename=\"".$filename."\"\r\n\r\n";
    $header .= $content."\r\n\r\n";
Suggestions, thoughts?