If you are a user with an account on the new website, please make sure to check what your game version is. If your game version is 0.72.3 and below, you will not be able to log in.
Online functionality in all previous clients (0.72.3 and below) rely on the API of our old website, which no longer exists.
If you want to be able to use your new EO account on Etterna right now, you can try out the latest test clients at the link below. Make sure to read the post carefully.