The closing of cases based on ServerHold/ClientHold is based on whois-lookups.

They are run for every "Unactioned" and "Open" case once every 24 hours.

If you want to trigger an early update, you can click the "whois" button in the case view.

This will both update the case view with fresh whois-data and if a ServerHold/ClientHold state is detected, the case will be automatically closed within the hour