I got troubling with following error when signing in Google. It make me crazy and waste of my time. I uploaded difficultly using command line to Google App Engine. I fainted as soon as I found the solution for that error. Of course, every problem is easy if you know the solution.
The solution is have to adjust your computer time with country time zone. 🙂 haaha Why don’t error message show to do that?
Reference : 400 Bad Request during oAuth handshake from Eclipse plug-in