Is X11 library required on a machine where Policy Server Management console is displayed when accessing to the Policy Server Management console remotely from another server?
X11 library is required on a machine of Policy Server since policy server administrative console is executed on the machine of Policy Server.
Policy Server Installation Requirements
https://docops.ca.com/ca-single-sign-on/12-6-01/en/installing/install-a-policy-server/policy-server-installation-requirements
Verify Required Linux Libraries
https://docops.ca.com/ca-single-sign-on/12-6-01/en/installing/install-a-policy-server/install-the-policy-server-on-linux