joomla 3.x login google + redirect error (400)

Jim,
Sorry you're running into issues with Google+. If you're seeing the Google error page with a little robot or something, there's usually a line that says something like "Error Details". It doesn't look like a link, but you can click it. Can you click it and see if more information popups up? If so, post it so we can see the message, and that will help us narrow down the problems.

I also just tried your site, but it's offline, so I couldn't recreate the error. If you want me to test, just let me know when the site is available, or Private Message me credentials so we can set the site Online.

Thanks,
Alex

Can you tell me what the Apache "mod_hive" module is and what that notice in the log is doing? Is the request being blocked or passing properly?

I do see that the referrer line is using https where the "matched URI" is not. I'd recommend trying to login over both http and https to see if there's a difference in results there.

Let me know anything you can about hive or if the http/https thing is a clue, and we'll gladly continue to help however we can.

Thanks,
Alex