I've do it, dont take this option:Make sure that the following setting is enabled in Main >> Server Configuration >> Tweak Settings: Proxy subdomains. This, along with some DNS A records, is all that is needed to make the feature work.
Non-SSL redirect destination > Hostname
SSL redirect destination > Hostname
But don't take effect.
when I go to
it redirects to: https://webmail.domain.com
instead of: https://server.hostname.com on which I have a Comodo valid SSL