I found a little work around for this (maybe a hack).
Logs/metrics are being sent to ES using HTTPS connection and ES nodes cluster communicate with each other using TCP connection. So, I am using our organisation’s certificate to accept all REST request for accumulating logs/metrics and opendistro’s default certificate for all TCP connections. Since I am using docker and swarm(for overlay network) to run my elastic stack, so I have removed the port mapping (9300) from docker-compose and stopped accepting any communication outside of the docker network to 9300 port.
After that I didn’t received any error(mentioned above) and my cluster is healthy.