I could figure out "my" problem: https://ubuntuforums.org/showthread.php?t=2441385
somehow the network device name seems to have changed form enp3s0 as written in the /etc/netplan/00-installer-config.yaml config file to enp2s0. Then, my network was not activated at boot-up any more.
I could figure out "my" problem: https:/ /ubuntuforums. org/showthread. php?t=2441385 00-installer- config. yaml config file to enp2s0. Then, my network was not activated at boot-up any more.
somehow the network device name seems to have changed form enp3s0 as written in the /etc/netplan/