Thanks for your inquiry. I believe we have resolved this issue through a Support Ticket. Please let me know if you have continued difficulties. Please ensure that you have upgraded to the current build of SmarterMail 13x to take advantage of any corrections and modifications to the application.
If I recall, there are two different Send Test on checktls.com website. There is the Basic and the AssureTLS test. The AssureTLS test may fail since SmarterMail does not issue a break command if TLS is not detected. The message would be sent in plain text.