unfortunately gms still uses the hostname for autodiscover. this is a hassle since nearly all gms machines reside on a local domain or public subdomain and email addresse reside on the domain. since autodiscover only works with ssl enabled you want to stick to a none used public subdomain such as intra.example.com so you don't have to transfer certificates to the client devices.

in order to have autodiscover working your gms hostname has to be a public one such as gms.example.com so that autodiscover will do the configuration job.

with that said i'm only able to access gms admin console via ip or public domain name when port 8120 is open on the firewall. ip will allways get a certificate warning and opening the port 8120 might not be best practice.

if anybody has setup multiple hostnames (public and local) for gms and still got autodiscover working, please let me know.