Comment 17 for bug 105378

What you are seeing is expected bevahior. Thunderbird (like most modern mail clients) supports the newer TLS protocol while most Microsoft mail clients support the older SSL wrapped port (SMTPS) approach on port 465. Setup for this is described here:

http://www.postfix.org/TLS_LEGACY_README.html#server_enable

You will see that there is an SMTPS line in your master.cf that is by default commented out. This is by design. If you are going to be doing much with Postfix, there are a lot of options, so you might want to get a book about it. Personally, I recommend "The Book of Postfix".