Active Directory configuration issue

I am using trying to configure active directory from ES 6.8 and getting error. Below is the snippet from active directory configuration from elasticsearch.yml file


xpack:
security:
authc:
realms:
my_ad:
type: active_directory
bind_dn: "CN=seracc,OU=Users,OU=None Restricted Accounts,OU= blabla,DC=blabla,DC=blabla"
group_search:
base_dn: "CN=blabla,OU=Groups,OU=blabla,DC=blabla,DC=blabla"
domain_name: blabla
order: 1
follow_referrals: false
url: "ldaps://blabla"

i am getting below error

missing realm type [xpack.security.authc.realms.active_directory.type] for realm

Please suggest

Try

xpack.security.authc.realms:
active_directory.my_ad:
bind_dn: ....