Hello,
This page deals with configuring Access Server with LDAP to Active Directory. It includes a section to enable SSL. That section includes a link to a page with more detailed information on settings for LDAPS.
https://openvpn.net/vpn-server-resources/openvpn-access-server-on-active-directory-via-ldap/
https://openvpn.net/vpn-server-resources/authentication-options-and-command-line-configuration/#ldap-authentication-commands
If this doesn't help I suggest you open a support ticket at
https://support.openvpn.net/
Kind regards,
Johan