If the hostname of your database changes, PAM will no longer be able to connect to the database. The database configuration is contained in the \pam\server\c2o\.config\OasisConfig.properties file. You can review and modify the hostnames directly in that file, or use the installer to reconfigure:
Knowledge Doc ID: TEC500533 "How do I reconfigure PAM to modify Ports, authentication and Database Settings?"
The installer allows you to test the connection to ensure it will work.