You should be able to login with the email address you registered your starter account with. I’m not sure what changes you’ve made to your code, but you could have added a feature that requires premium graphics. Realistically all you should have had to do is add:
graphicsCompatibility = 1
to your config.lua where you set the width and height and drop the sprite library in. There shouldn’t have needed to be much in the way of changes.
Can you try building the “hello world” sample app?