Ubuntu server 16.04 won't boot after installation, Fail to start LXD

I am new to Ubuntu. Just installed Ubuntu server 16.04 onto Dell R730 server yesterday. The first time reboot was okay. But the server refused to boot today. The error message was: Failed to start LXD.

boot messages

Can anyone please help?


Solution 1:

This problem is after upgrade. LXD service needs to be restarted using the root account.

sudo service lxd restart

You have to reboot afterwards, e.g. using this command:

sudo reboot