If both your StarDot device and your time server or NVR are on a private LAN and the camera does not need access to the Internet, make sure all three DNS entries are empty (Network tab). Enter the time server or NVR's IP address in the Time Server field on the Date/Time tab.
If your NVR or time server is on a network outside the StarDot device's network, make sure your gateway and DNS is properly configured in the StarDot device (Network tab). Enter the NVR or time server's hostname or IP address in the Time Server field on the Date/Time tab.