You must enable NTP authentication for the NTP client, and then specify the IP address for the NTP server and the authentication key sent to the NTP server. Otherwise, if NTP authentication fails, then no synchronization will take place. In general, for successful NTP authentication, you must completely configure the NTP client and server.
On a LAN, the device with high clock precision functions as the NTP server, and other devices are synchronized to the clock of the NTP server. In the broadcast mode, you do not need to specify a server for the client, and the client listens to packets sent from the broadcast server in real time.