Hi
I have installed both 3.6 and 3.7 and have the same smtp connection issues. My server port 25, 465, 587 are all open. SMTP services have also been installed. You can even telnet into smarthalal.org.au 25 and get a response. However, when you test configuration within Moodle you get connection not established. Please help.
NB - netstat and ufw shows ports are open and listening.