Since Rx-Universe does not support VSS (Volume Shadow Services), file are actively being written to tables and databases. In order to allow a successful backup, you will need to stop/start Rx-Universe transnational sessions. This can either be done manually or automatically scheduled.
Scheduling Stop/Start time.
1) In Rx-Universe got to Setup→ System Settings and click on General Tab.
2) Set the "Time to shut down" and "Time to restart". It would be a good practice to test how much time your backup software takes to successfully backup the Rx-Universe files, it would help minimize the gap of downtime between shutdown and restart.