Ask HN: a good/simple oauth frameworks for webapps

me and my startup are creating our first web app, and are using https://www.accountchooser.com/ when it works, it works. unfortunately it fails to authenticate users about 50% of the time :( I'm not sure if it's our fault, but there isn't a support forum to ask :( any recommendations for a better choice? FYI we are using python2.7 on GAE, if that matters