Completing the standard email/password account creation
If you are attempting to create a new standard email/password account and you are receiving a message stating an account with that email already exists, it might mean that the account was started but never verified.
First, try logging in with that same email and resetting your password. If you are unable to reset your password, it means your email must be verified first.
You can resend the email verification to successfully complete your account by clicking Verify Email on the login page.
Then you should be able to login successfully and reset your password if needed.