Add the following parameters in the /etc/rc.conf configuration file:

ntpd_enable=”YES”
ntpd_sync_on_start=”YES”

add the line: pool de.pool.ntp.org iburst in /etc/ntp.conf file

iburst denotes that ntpd will perform a burst of 8 quick packet
exchanges with a server when contact is first established, to help quickly synchronize system time.

The de prefix differs depending on the servers of the country you choose. In my case Germany. A complete list of active servers is on https://www.ntppool.org/en/

In addition, FreeBSD provides a project-sponsored pool, 0.freebsd.pool.ntp.org.