Elasticsearch 7.16.2 config for a cluster

Question

I try to setup a ES cluster with 2 Nodes. Everything works fine without SSL but with the certificates no connection between the 2 Nodes can be made anymore.

cluster.name: elasticsearch-stage
ingest.geoip.downloader.enabled: false
path.data: E:\Elasticsearch-Staging\data
path.logs: E:\Elasticsearch-Staging\logs

network.host: 0.0.0.0
http.port: 9200

discovery.seed_hosts: ["172.16.98.177", "172.16.98.198"]
cluster.initial_master_nodes: ["172.16.98.177"]

xpack.security.enabled: true
xpack.security.transport.ssl.enabled: true
xpack.security.transport.ssl.verification_mode: certificate 
xpack.security.transport.ssl.keystore.path: elastic-certificates.p12
xpack.security.transport.ssl.truststore.path: elastic-certificates.p12

Master node has: node.name: stage-node-1

Second node has: node.name: stage-node-2

I ran bin/elasticsearch-setup-passwords auto to create the system user passwords.

I ran bin/elasticsearch-certutil cert -out config/elastic-certificates.p12 -pass "" on the master node to create the certificate and copied the certificate and the keystore file to the second node.

I'm able to access http://172.16.98.177:9200/_cluster/state/nodes?pretty which is the master node when I'm connected to the master node.

But when I start the second node it is not able to connect to the master node. Can someone help me out here?