For all the Planners/WSA, SSO authentication is not working through the APPS login in the NEW UX. But SSO is enabled, and it is working appropriately with the classic dashboard login.
Note: We are managing the workaround. The workaround will be, first, login to the model and then log in to the APPS.
I request Anaplan to provide a solution to allow users to log in to APPS with the SSO.