yesterday I setup a NetSUS server just to use the SUS appliance. I was able to log into with the default webadmin / webadmin credentials. I didn't change them. But now today I can't login. Even after rebooting.
I had a similar issue this morning. I started a sync last Friday and since JAMF has still not updated the appliance, it filled up the 200GB drive. SSH'd in, expanded it by another 100GB and rebooted, and all was good.