Elasticsearch HTTP Basic Authentication

Hi Team,
I am deploying elasticsearch by integrating with keycloak and searchguard. Below is the http configuration is used in searchguard.

  authc:
  basic_internal_auth_domain:
  http_enabled: true
  transport_enabled: true
  order: 0
  http_authenticator:
  type: "basic"
  challenge: false
  authentication_backend:
  type: "intern"

Here authentication will happen via keycloak so the challenge flag is set to false( challenge: false).
Once the elasticsearch is deployed ,we are getting below error message in elasticsearch client:-

    **{"type":"log","host":"belk-efkc-belk-elasticsearch-client-c4f8685bb-lxfp7","level":"WARN","systemid":"2106a117733f42d697284fbc54927928","system":"BELK","time": "2020-10-07T01:38:43.439Z","logger":"c.f.s.h.HTTPBasicAuthenticator","timezone":"UTC","marker":"[belk-efkc-belk-elasticsearch-client-c4f8685bb-lxfp7] ","log":{"message":"No 'Basic Authorization' header, send 401 and 'WWW-Authenticate Basic'"}}**

Can you guys please help here to reolve the issue.

Regards,
Varun S

Which version of Search Guard and Elasticsearch are you using?