Error message for unauthorized user

Summary

Our full employee population is not loaded to HCM cloud as workers, this is intentional. Is it possible to present a meaningful message?

Content

We are using SSO via an on-premise IDP.  If an unauthorized user attempts to log in, the error message indicates “Bad Request - The request could not be understood by server due to malformed syntax.”  Is it possible to access a error message catalog to present a message meaningful to an end-user?  Or redirect to a page where we present a message indicting user is not authorized?