Hi!
Thank you for you message. Indeed, there is some kind of problem regarding the login. I will take a look at it.
At this moment, I’m changing the behaviour of the app and the backend, to remove everything to do with in-app ads, and in-app purchases.
From the next version, the app will be free and will not have any kind of ads or in-app purchases.
It is possible that because of this it may take a little longer to resolve the bug you have reported. Please give me a few days of margin.