I believe there is a bug in the SMTP server interface in the new email functionality in v12.0.0. My tests to the SMTP server fail with a 'timeout' error and what I see with Wireshark is VarAC establishing a TCP connection with the mail sever and then doing nothing, instead of sending a Client Hello message when port 465 (SMTPS) is selected. Then VarAC times out and closes the connection.
I think what is happening is that VacAC is fixed in STARTTLS mode (as would be used with port 587) and is waiting for a Hello message from the server, and not hearing one times out. This is the correct mode of operation for port 587 (STARTTLS) but not 465 (SMTPS) , which some mail servers still use. What should happen is that VarAC should look at the TCP port selected (465 or 587) for SMTP service and choose the correct protocol (SMTPS for 465 or STARTTLS for 587) accordingly. Please let me know if I can be of any assistance in testing.
I'd be happy to help, I sent you a response via email.