Outlook 2011 TLS / STARTTLS encryption bug with some IMAP servers

Hello,

I discovered a TLS bug with Outlook 2011 14.4.4 under certain circumstainces with some IMAP servers. When the particular IMAP server has no regular SSL support but only TLS 1.0  on port 143 enabled,  Outlook 2011 is unable to authentificate with the IMAP server.

For example here's a welcome message of a IMAP server which only accepts a login via TLS on port 143. There are no other SSL ports like 993 available on this server, only STARTTLS is allowed.

* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE STARTTLS LOGINDISABLED] imapd ready.

Settings in Outlok 2011 are:

(x) IMAP

(x) "Dismiss standard port", i did enter 143 as port (tried also without this option, no change)

(x) "Enable SSL for connection (Suggested)"  (tried with and without, no change)

Wireshark reveals the following:

.7.................@.....
...................yo=E.....H."* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE STARTTLS LOGINDISABLED] imapd ready.
.7... BAD Error in IMAP command received by server.

The IMAP server DEFINITELY correctly configured to accept connections via Port 143 with TLS/STARTTLS. It's working with all other Mail Clients including Apple's Mail on OSx, as well as the built-in Mailclient in iOS.

The bug does not seem to affect SMTP connections and authentification,  somehow SMTP with TLS is working without issues with Outlook 2011 14.4.4.

Thanks

Dominic