conf: unknown section: memcached at depth

[yehaotong]

Startup failed：conf: unknown section: memcached at depth 1038795903
nutcracker: configuration file '/etc/nutcracker.yml' syntax is invalid
and I check my nutcracker.yml:

                        memcached:
                          listen: 0.0.0.1:11211
                          hash: fnv1a_64
                          distribution: ketama
                          timeout: 400
                          backlog: 1024
                          preconnect: true
                          auto_eject_hosts: true
                          server_retry_timeout: 30000
                          server_failure_limit: 3
                          servers:
                            - $MEMCACHED_TW_SERVER:1

Is that any error on my nutcracker.yml?

[TysonAndre]

It might be an issue with your indentation. Is memcached further indented than previous sections?