To verify if NTP synchronization service is active in your system, use the command given below:

timedatectl

If it’s disabled, just type this to enable it:

sudo timedatectl set-ntp True

You can change the synchronization server in the timesyncd.conf configuration file:

sudo nano /etc/systemd/timesyncd.conf

Now, you can check the correct synchronization with the command:

timedatectl timesync-status