Once, I did an update and after said update, when I launched the game, it lost my login criteria and took me to a screen that asked me if I had an account or not. I had to retype in my credentials and let it verify that I did indeed have a valid account. Might something like this have happened to you and you accidentally hit the option that you didn't have an account, in which case it would ask you do do what you're saying? Try to close it out and relaunch this?

It could possibly be an account oversight which you'd have to get into direct contact with support for, but you can easily check this by logging into your account via mogstation and verifying that your account is still active and still has subscription time.