I have been having some Briefcase and Documents issues with all the accounts on my Zimbra server.
I discovered in the page source of my browser that the URL's in the Briefcase and Documents are not HTTPS, just plain HTTP. This is a problem since all the virtual domains are set to use HTTPS. In the domain config from the admin web login, I have public service host name set to mail.domain.com which is also what the virtual host name is. Should the public service host name be set to https://mail.domain.com instead. I can not seem to find a lot of info on public service host name and I'm thinking that may be why the Briefcase and Documents URL's may be broken.