For some reason, the default admin user account and password did not appear to exist in the instance of bitnami Joomla that I installed on my AWS through Lightsail.
To set your Joomla admin password:
- Log in using an SSH terminal. You can do this through your Web browser from your AWS control panel.
- Go to /apps/joomla.
- Type sudo ./bnconfig --userlogin admin --userpassword password
- You should now be able to log in using username: admin and password: password.