Hey, I'm getting almost exactly same symptoms on 3 new installs. "failed to connect" error and the "try again" click box. Usually I can get through to Google, almost anything else gives me a failed to connect error. I am also finding that I cannot login to the Untangle via the network interface, as if somehow my password or user name has been changed.
This is very embarrassing to have all these machines fail. I do the install, everything is running tits, next morning (or a day or so later) nothing seems right or is outright hosed. I think a hacker has found a hole.
I have yet to see one of these installs last longer than 3 days before this happens.