Forum OpenACS Development: Re: AcsMailLite - Lost on debugging
The man page  mentions as well that smtp servers have recently deactivated SSLv3 because of the POODLE attack. If the simple smtp client essentially doing the same as acs-mail-lite fails, please activate tls1 manually from the smtp client script as indicated on the man page. if this helps, we will find a way to do this automatically from acs-mail.lite
I solved the problem by cleaning up SMTP* parameters.
a smtp client script would increase my odds. I'd be glad if you guide me trough it.
On another front, acs-mail-lite doesn't have the same essentials than simple SMTP. Otherwise, it would work when ACS-MAIL-LITE->SMTP-* parameters are filled in. Perhaps I didn't understand your statement.
a) acs-mail-lite uses finally tcllib's smtp package
b) you asked, how to debug smtp without OpenACS interference (your formulation "How would I make sure OACS layer is not the guilty". The answer is to call tcllibs smpt package functions via a small script without OpenACS (as indicated in the man page). You can call this script from the shell with any option (look at the options of .::smtp::sendmessage in the manpage). If find a options combination that works from the script, you can check afterwards, how to pass these options via acs-mail-lite. If you find NO combination of options that work, then acs-mail-lite can't do anything, and you have to debug tcllibs smtp.
But since have have fixed out already you misconfiguration, there is no need for going this way.