Email Function attachment not working

Content

Dear All,

Please help me

I'm trying to generate one .pdf file and send mail to user, i sending mail correctly, but attached .pdf not opening due to content type issue. Error: "file damaged or decoded issue".

Below is my code:

try 
        {
            $email = new RNCPHP\Email();
            $email->Address = $email_1;
            $email->AddressType->ID = 0;
            $email->content_type
            $mm = new RNCPHP\MailMessage();
            $mm->To->EmailAddresses = array($from);
            $mm->Subject = "Test from RNCX";
            $mm->Body->Text = $text_body;
            $mm->Body->Html = $message;
            //$mm->Headers[] = "Content-Type: application/x-www-form-urlencoded";
                

                $fattach = new RNCPHP\FileAttachment();
                $fattach->ContentType ="application/pdf";  
                $fp = $fattach->makeFile();
                fwrite( $fp, "Making some notes in this text file for the Contact".date("Y-m-d h:i:s"));