Unable to comunicate elastic search server 6.2.3 usingrest high level client

Hi Team,

We have elastic search server 6.2.3 it is installed in MDM 10.3 .we have certificates for elastic search server it is working fine in browser.

when I try to call the rest high level client it is not working.always getting below errors
MDM_ESKEYSTORE_FILE_JKS.keystore

  Error : Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

.P12 certificate also same issue.

Please do the needfull