You can have your Synology NAS serve as a network time server to synchronize time between different network devices and the Synology NAS over network.
Tick Enable the NTP service and click Apply.
Note: The NTP service is required for Surveillance Station and High Availability cluster. Therefore, if you have Surveillance Station or High Availability Manager installed and run on your Synology NAS, the service cannot be disabled while the package is running.