This is something that I posted in the initial announcement thread. I suspect it's not the most obvious place to look for answers to problems, since some new threads seem to be about the same issue(s). So, here goes.
The appliance seems to be very particular about DNS in the environment where it runs. Anything short of perfection may cause one or both of the problems below.
Problem 1: You install the appliance, but can't connect to it. The browser returns "connection reset" or "unreachable" (depends on the browser). If you used another client system, and it worked, and you connected the appliance to your VCenter, the original system's VCenter Client still shows that the plugin is disabled due to connection error. Network dump shows that the TCP handshake succeeds, but the appliance resets the connection after the first HTTPS packet.
Cause: The appliance is configured using default SUSE security settings, which include "ALL : KNOWN" line in /etc/hosts.allow. This line dictates that the client IP must be reverse resolvable to a name and then back from the name to the same IP. If your environment doesn't have reverse DNS that matches exactly with direct DNS, the check may fail, and the server will close the connection.
Resolution: Use the console to connect to the command line (login as "root" / "admin"), and change the above line to "ALL : ALL". You need to know how to use vi.
Problem 2: You have connected to the appliance, the plug-in works, but the appliance screen is stuck on initialization.
Cause: The appliance can't resolve its own name.
Resolution: If you use DHCP for the appliance: use the admin web page to disconnect the appliance from VCenter, give the appliance a static IP, create an A record for it in your DNS system, reboot, reconnect to VCenter. If you gave the appliance a static IP: make sure the hostname you specified is resolvable to the same IP.
