(17 Apr 2016, 7:14 pm)Jamie M wrote Keeps profusely telling me that "The login has failed - Please try again."
Done the basic uninstall - reinstall - update et cetera, few other people have had the issue looking at the app comments in the store.
I found the app was a bit glitchy when my S6 Edge upgraded to Marshmallow, but clearing the cache and data helped. I gave up on my old login and used a newer gmail one and that seemed to cure my issues too.
My only annoyance was the lack of screenshot ability. There's ways around it though.