To log in as the local admin user while the appliance is configured to use a different login method such as Active Directory for example, you need to click on the local login link which is located under the login button.
This will open a local login window which can be used for Local users authentication.
As a consequence of this change, all other local users can be authenticated using the local login link not just the admin user. To prevent unauthorized access, if the appliance is configured to use a login method that is different from local, the passwords of all non-admin local users are reset during the upgrade.
After the upgrade, if you want to re-enable login for the locked out non-admin local users, you can set a new password for them. As the local login is always active, the admin fallback option for the X.509 login is deprecated.