If you are willing, I would go to the App on your Android Device, long press on the icon and choose App Info. Then do a force stop and go to the Storage and Cache and clear Cache.
Restart your device and try to login. If you get login failed, just wait on the screen for about 30 seconds to a minute and select Try again or Login and see if it works.
I have run into this in the past, but the second attempt without restarting the app or doing anything special seemed to work