1. Change the Administration interface TCP port to custom port, after change and saved, you have to connect to the custom port in your browser.
2. Go to the Web Server, enable the HTTPS.
After doing the above, I am now able to access the webmail component over both SSL and non-SSL, so thank you for that. Trying to connect Outlook from outside the network still does not work, however. Still getting the same error about not being able to resolve my user name to an account on the server.
I did follow the instructions at
http://doc.zentyal.org/en/openchange.html. The only difference between those instructions and what I am doing is that my "Exchange Server" (usually the internal name of the server, in an Exchange environment) and "Exchange Proxy" server (usually the external host name from outside) values are different. In the official example, it uses the same server name for both (which is actually an internal, non-routable host name, so maybe the doc should be updated?).
In my first post, I indicated the external host name and the internal host name of my server.
I have just confirmed that RPC proxy *is* enabled, and both the "without SSL" and "with SSL" boxes are checked.
The only other thing is I just have the default self-signed certificate on the server; I do not have a "trusted" certificate on there, nor have I enabled the Certificate Authority and generated a certificate from that module. Do I need to do either of things, or should I be able to use the default self-signed certificate?
I am able to connect an Outlook client on the same internal network as the server no problem, so I know that fundamentally the server is working; it just seems the RPC proxy is not.
On the Zentyal server, I have also completely disabled the firewall. Since it is already behind a NAT firewall, I set the "external" rules to allow *all* traffic (i.e., I deleted all the existing rules and have just one that is allowing anything from anywhere), so I do not believe it is a firewall issue.
I hope this helps shed some light?