how did you setup SSL? Have you generated certificates? See https://www.elastic.co/guide/en/elastic-stack-overview/7.3/encrypting-internode-communications.html
Also, there is a dedicated Elastic Cloud for Kubernetes Operator that has recently been released (with Elasticsearch 7.2 - you might want to try with a more recent version anyway). See https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-quickstart.html
In general I would try to setup Elasticsearch with TLS/Auth without Kubernetes first, see if that is working and then go from there.