Question about sendmail by smtp

Hi all

I try to send a email by smtp.
format is : smtp = Net::SMTP.start ‘127.0.0.1’,‘account
[email protected]’, ‘password = xxxxx’, ‘authtype =:plain’ # i also test
authtype=:login
but it returns SMTP-AUTH requested but missing secret phrase.
who can help me resolve it?
thanks everyone.

Sandy