If your computer is able to resolve the hostname of your server outside of the network but not able to connect to it’s authentication service then the loginwindow process will just hang. This will cause the screensaver login window or main login window to also hang. There could be a number of reasons this would happen. For example firewall issues connecting to your server or just that the server hostname resolves to another server outside of the network.

My particular problem was that godaddy’s wildcard DNS was resolving all addresses *.hostname.com to it’s advertising pages. So even though i had no entry for my server in global dns it would still resolve and attempt to connect. Removing the wildcard DNS in my godaddy settings fixed this instantly.