How to connect to newly installed Oracle XE instance?
I figured out the issue.
I was using domain login to install Oracle XE. If you are using domain login to install Oracle XE then the database creation will fail (though you may not get any error messages on that regard).
Solution:
Install Oracle using a local admin user.
Change SQLNET.AUTHENTICATION_SERVICES to (NONE) in sqlnet.ora.
Now login with your domain user to use oracle XE.