Not able to send email through MAc perl.

Hi ,

I want to send email through MAc perl. I have an SMTP server and my OS
is MAC.

I used Mail::Sender perl module and was successfully able to send
email through windows platform. But if I execute same script on MAC OS
it is giving me error saying authentication required.
Following is my code snippet.

#!/usr/bin/perl
use Mail::Sender;
     $sender = new Mail::Sender {
                smtp => 'smtpserverIP',
                from => 'sender_Email'
        };
        die "Can't create the Mail::Sender object: $Mail::Sender::Error
\n"
                unless ref $sender;
        ref $sender->Open({
                to => 'receiver_Email',
                subject => 'test mail.'
        })
                or die "Can't open the message: $sender->{'error_msg'}
\n";
         $sender->SendLineEnc("Hi");
        ref $sender->Close
                or die "Failed to send the message: $sender-
>{'error_msg'}\n";

On executing the script I am getting following error:
Can't open the message: Server error 503 5.0.0 Authentication
required"

Please help me to make this work. Also is there any other way of
sending an email through Mac perl.

Thanks,
Rapunzel