Your error message is utterly useless - please give some idea of what went wrong
I have downloaded your app to my Windows 10 laptop, and tried to sign in.
All I get when trying to sign in is a pop up window that says "undefined", with an OK button to close it that kicks me back to the login screen.
How useless is that?
I have two accounts, one is with BT, the other is yahoo UK linked to Flickr. Both of them give this useless error message when I try to sign in.
If I click on the having trouble signing in, the note below suggests "Having repeated difficulty signing in?
Clearing your browser's cache and cookies may help."
IT'S AN APP, NOT A BROWSER. HOW DOES THIS MESSAGE HELP AT ALL?