Yesterday when the site was down the Android app was also affected. So it wouldn't have worked for anyone during that time.
If you try it again (and make sure your internet is enabled) it should work now. If it's still giving you that error you could try going into the settings and then tapping "create new account key".
After I add my account in the app using the QR code, I go back to the main screen I have always gotten the following message: "Unable to connect. Please check your internet connection." I've tried using my account in the app a bunch of different times and have never been able to get it to work. I suppose creating a new account in the app would be a viable work-around....
Thanks!