Hi Amer
did you already try to append the "s" into your HOST Url value if you're actually using the ldap:// syntax e.g. ldaps://192.168.1.100? and check Use TLS?
There is another step i.e. to trust the certificate coming from your AD: give https://docs.moodle.org/38/en/LDAP_authentication#Enabling_LDAPS_on_your_Moodle_server and following sections a read.
HTH,
Matteo