I have issue with my Zimbra Mail Server 6.0.7. In that i have configured HTTPS for client login and for whole session. but it stills communicate in http based authentication. due to that some sniffing software are easily sniffing details.
So how do i configure completely HTTPS in Mail server from login session to end of session.
The simple answer is you have to re-configure the server side to run on https .
I have only used version 7 and 8 is now available. If you can successfully transfer the data, it might be time to upgrade. I am assuming that you are using the open source version.