If your organisation has SSO enabled and your employees get the error 'Error, the User is a Federated User. Click Next to Login' when trying to log in, it means they are trying to log in using the non-SSO screen.
To resolve this issue advise the user to log in via the SSO screen.
If an employee has been assigned user role Admin, they will also need to setup two factor authentication. If the employee hasn't set this up you will see the following message when trying to login the database 'Your account requires two-factor authentication. Please contact your system administrator to get set up'.
To resolve this issue, resend a reset two-factor authentication link to the affected employee which should allow employee to set it up successfully and access the database.