in reply to
Re^2: connection not established. error in Mail::Sender
in thread connection not established. error in Mail::Sender
The "This message is in MIME format. ..." is just a message for the (I believe very rare) people that use a mail client that do not understand MIME (the standard that defines all those headers and stuff allowing you to send multipart messages, attachments etc.) Ignore it.
I don't understand what where gives you that error. There's something you haven't shown.
Enoch was right!
Enjoy the last years of Rome.