If you didn't configure LLDP and try to show neighbors detail, this will result in an error.
sever@vyos-1.3-roll:~$ show lldp neighbors detail 2020-04-18T13:05:42 [WARN/control] unable to connect to socket /var/run/lldpd.socket: No such file or directory 2020-04-18T13:05:42 [WARN/lldpctl] not able to get the list of interfaces. Unable to connect to lldpd daemon ------------------------------------------------------------------------------- LLDP neighbors: -------------------------------------------------------------------------------