EV Nova is set to do a version check on startup by default. It connects to the Ambrosia server to see if there is a newer version available. If you have any software like Little Snitch installed that monitors and prevents such connections, this can happen. Try this - disconnect your computer from the internet. Disable Little Snitch and launch Nova. Then click on Set Prefs. Deselect the "Check for updates" option. Enable Little Snitch, reconnect to the internet and Nova should launch just fine.