Just downloaded the Android beta. When I tried to log in with artemis.camp, it took me to Firefox, where I logged in and pressed authorise, and then I went back to Artemis and it said waiting for browser. Now when I press the artemis.camp button again it brings me to a white screen in Firefox, and still says waiting for browser.
I also couldn't log in. Tried multiple browsers. Uninstalled, installed and then I went to login right away without doing anything else. Then it worked.