LDAP for ES/Kibana on GKE with istio reverse proxy

Hi everyone, I am trying to implement LDAPS authentication for my Elastic cluster deployed on GKE which has Istio with Strict mTLS setup.

The configuration works fine when I test from docker running on my laptop but the same doesn't work when I try this from elastic on GKE .

Getting the below error message. Any help is appreciated.

Authentication to realm ldap1 failed - authenticate failed (Caused by LDAPException(resultCode=91 (connect error), errorMessage='An error occurred while attempting to connect to server <>:<>: IOException(LDAPException(resultCode=91 (connect error), errorMessage='Unable to verify an attempt to establish a secure connection to '<>"<>' because an unexpected error was encountered during validation processing: SSLPeerUnverifiedException(peer not authenticated), ldapSDKVersion=6.0.3, revision=<>'))'))

elasticsearch:
  secureSettings:
    - secretName: elasticsearch-ldap-secret
      entries:
      - key: xpack.security.authc.realms.ldap.ldap1.secure_bind_password
xpack.security.authc.realms:
  ldap:
    ldap1:
      order: 2
      enabled: true
      url: "ldaps:<>:<>"
      ssl:
        certificate_authorities: /usr/share/elasticsearch/config/ldap-cert.pem
      bind_dn: "uid=<>,ou=<>,dc=<>,dc=<>"
      user_search:
        base_dn: "ou=<>,dc=<>,dc=<>"
        filter: "(uid={0})"
      user_group_attribute: "isMemberOf"
      unmapped_groups_as_roles: false


  spec:
    volumes:
    - name: ldap-cert
      secret:
        secretName: elasticsearch-ldap-cert-secret