SSL(curl) connection error in ElasticSearch setup - docker

Question

Have setup a 3-node Elasticsearch cluster using docker-compose. Followed below steps:
On one of the master nodes, es11, gets below error, however same curl command works fine on other 2 nodes i.e. es12, es13:
Error:
curl -X GET 'https://localhost:9316'
curl: (35) Encountered end of file
Below error in logs:
"stacktrace": ["org.elasticsearch.transport.RemoteTransportException: [es13][SOMEIP:9316][internal:cluster/coordination/join]",
"Caused by: org.elasticsearch.transport.ConnectTransportException: [es11][SOMEIP:9316] handshake failed. unexpected remote node {es13}{SOMEVALUE}{SOMEVALUE
"at org.elasticsearch.transport.TransportService.lambda$connectionValidator$6(TransportService.java:468) ~[elasticsearch-7.17.6.jar:7.17.6]",
"at org.elasticsearch.action.ActionListener$MappedActionListener.onResponse(ActionListener.java:95) ~[elasticsearch-7.17.6.jar:7.17.6]",
"at org.elasticsearch.transport.TransportService.lambda$handshake$9(TransportService.java:577) ~[elasticsearch-7.17.6.jar:7.17.6]",
https://localhost:9316 on browser gives site can't be reached error as well.It seems SSL certificate as created in step 4 below is having some issues in es11.
Any leads please? OR If I repeat step 4, do i need to copy the certs again to es12 & es13?
Below elasticsearch.yml
cluster.name: "docker-cluster"
network.host: 0.0.0.0
Ports as defined in all 3 nodes docker-compose.yml
environment:
- node.name=es11
- transport.port=9316
ports:
- 9216:9200
- 9316:9316
Initialize a docker swarm. On ES11 run docker swarm init. Follow the instructions to join 12 and 13 to the swarm.
Create an overlay network docker network create -d overlay --attachable elastic
If necessary, bring down the current cluster and remove all the associated volumes by running docker-compose down -v
Create SSL certificates for ES with docker-compose -f create-certs.yml run --rm create_certs
Copy the certs for es12 and 13 to the respective servers
Use this busybox to create the overlay network on 12 and 13 sudo docker run -itd --name containerX --net [network name] busybox
Configure certs on 12 and 13 with docker-compose -f config-certs.yml run --rm config_certs
Start the cluster with docker-compose up -d on each server
Set the passwords for the built-in ES accounts by logging into the cluster docker exec -it es11 sh then running bin/elasticsearch-setup-passwords interactive --url localhost:9316

Answer 1

(as per your https://discuss.elastic.co thread)
you cannot talk HTTP to the transport protocol port, which you have defined in transport.port. you need to talk to port 9200 in the container, which you have mapped to 9216 outside the container
the transport port runs a binary protocol that is not HTTP accessible