I'm guessing this is something to do with my apache / dns config, but I don't seem to be able to access webmail for my Zimbra server on the Internet. I can access both the admin and user webmail logins on the server itself using https, but I can't access it externally: "This web page is not available". I was assuming if I typed https://mail.mydomain.com, i.e. the host name of my server this would bring up the webmail login, but no joy.

The server is on a DMZ behind a NAT router / firewall with a static public IP. I can send and receive email fine from the server. Can anyone point me in the right direction?

Any help greatly appreciated.