Please note that both the systems are having same versions of Authen::SASL::Perl.

I tried $smtp->message. For "new" I get the following output:

pop.myserver.com
PIPELINING
SIZE 20480000
VRFY
ETRN
AUTH PLAIN LOGIN
8BITMIME
[download]

For "auth" I am not getting any return values, instead:

Unknown callback: 'authname'. (user|auth|language|pass)
[download]

Now, I am trying with Ethereal to troubleshoot this.

By the way if you have any more suggestions please let me know.

Thanks