1) Open the tweaks.json file (as administrator) found in \Program Files\Zerto\Zerto Virtual Replication\Gui.
2) There should be a tweak already in the file called t_idleLogOffTimoutSeconds, which will be set to 1800 by default (30 minutes).
3) Replace "1800" with the desired amount of seconds for idle timeout.
4) Restart the ZVM service.
NOTE: By setting this value to "0", the feature is effectively turned off and the idle logoff will no longer continue.