@KirAsh4
I finally got it running. It turned out that the sync.- problem is well known since May 2016.
–> https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=149221
stopped the ntpd with :
sudo systemctl stop ntp
rather than running ntpdate, ran ntpdate-debian:
sudo ntpdate-debian
started ntpd
sudo systemctl start ntp
check
sudo ntpq -p
Now I´m happy!!