# netplan --debug apply
** (generate:17302): DEBUG: 04:33:06.031: Processing input file /etc/netplan/01-network-manager-all.yaml..
** (generate:17302): DEBUG: 04:33:06.031: starting new processing pass
/etc/netplan/01-network-manager-all.yaml:5:1: Error in network definition: unknown key 'nameservers'
nameservers:
^