I installed the Android app on two different devices, and I am unable to log in to either one. I tried both my own account (triple-checked the username and password, same as the one I use on the web site), as well as the test account listed on the Google Play Store page for the app: firstname.lastname@example.org, password: sandbox. All I get is:
"Login failed, input username or password for AppFirst user, or this is network issue"
I have tried on several different networks, always with the same result.