Issue trying to het Kibana talking to Elasticsearch - elasticsearch

Question

I have Kibana and Elasticsearch on separate VMs.
Elasticsearch IP: 10.3.30.209
Kibana IP: 10.3.30.211
I am unable to curl the IP:PORT of Elasticsearch from Kibana:
curl 10.3.30.209:9200
curl: (7) Failed connect to 10.3.30.209:9200; Connection refused
The firewall on Elesticsearch server is listening for port 9200:
firewall-cmd --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: ens192
sources:
services: ssh dhcpv6-client
ports: 9200/tcp
protocols:
masquerade: no
forward-ports:
source-ports:
icmp-blocks:
rich rules:
The Elasticsearch service was at least starting up before I modified the elasticsearch.yml file to enable listening on the elasticsearch port and bind the Kibana IP:
network.host: 10.3.30.211
# Set a custom port for HTTP:
#
# http.port: 9200
http.port: 9200
Error when starting service:
systemctl status elasticsearch
● elasticsearch.service - Elasticsearch
Loaded: loaded (/usr/lib/systemd/system/elasticsearch.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Fri 2018-06-29 14:06:49 CDT; 1s ago
▽
Docs: http://www.elastic.co
Process: 6382 ExecStart=/usr/share/elasticsearch/bin/elasticsearch -Des.pidfile=${PID_DIR}/elasticsearch.pid -Des.default.path.home=${ES_HOME} -Des.default.path.logs=${LOG_DIR} -Des.default.path.data=${DATA_DIR} -Des.default.path.conf=${CONF_DIR} (code=exited, status=1/FAILURE)
Process: 6380 ExecStartPre=/usr/share/elasticsearch/bin/elasticsearch-systemd-pre-exec (code=exited, status=0/SUCCESS)
Main PID: 6382 (code=exited, status=1/FAILURE)
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: at java.lang.Thread.run(Thread.java:748)
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: Refer to the log for complete error details.
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: [2018-06-29 14:06:49,189][INFO ][node ] [Turac] stopping ...
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: [2018-06-29 14:06:49,199][INFO ][node ] [Turac] stopped
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: [2018-06-29 14:06:49,200][INFO ][node ] [Turac] closing ...
Jun 29 14:06:49 elasticsearch01 elasticsearch[6382]: [2018-06-29 14:06:49,204][INFO ][node ] [Turac] closed
Jun 29 14:06:49 elasticsearch01 systemd[1]: elasticsearch.service: main process exited, code=exited, status=1/FAILURE
Jun 29 14:06:49 elasticsearch01 systemd[1]: Unit elasticsearch.service entered failed state.
Jun 29 14:06:49 elasticsearch01 systemd[1]: elasticsearch.service failed.
NOTE: I am able to ping the Elasticsearch server from Kibana.
Any help with figuring out why this change breaks the Elasticsearch service and how I might be able to connect my Kibana server to Elasticsearch would be appreciated!