How to restart my elasticsearch? - elasticsearch

Question

I installed it yesterday on my desktop(Ubuntu 16.04)
elasticsearch.service - Elasticsearch
Loaded: loaded (/usr/lib/systemd/system/elasticsearch.service; disabled; vendor preset: enabled)
Active: failed (Result: exit-code) since уто 2018-04-17 10:18:51 CEST; 2min 58s ago
Docs: http://www.elastic.co
Main PID: 20185 (code=exited, status=1/FAILURE)
апр 17 10:18:44 jh-System-Product-Name systemd[1]: Started Elasticsearch.
апр 17 10:18:51 jh-System-Product-Name systemd[1]: elasticsearch.service: Main process exited, code=exited, status=1/FAILURE
апр 17 10:18:51 jh-System-Product-Name systemd[1]: elasticsearch.service: Unit entered failed state.
апр 17 10:18:51 jh-System-Product-Name systemd[1]: elasticsearch.service: Failed with result 'exit-code'.
I have tried both
sudo update-rc.d elasticsearch defaults 95 10
sudo systemctl start elasticsearch
I have changed network.host and port in elasticsearch.yml
network.host: 192.168.0.1
http.port: 9200
I have done what Val suggested
sudo /bin/systemctl daemon-reload
sudo /bin/systemctl enable elasticsearch.service
If I go for
sudo journalctl -f
then I have
kibana[16891]: {"type":"log","#timestamp":"2018-04-17T08:37:39Z","tags":["warning","elasticsearch","admin"],"pid":16891,"message":"Unable to revive connection: http://localhost:9200/"}
kibana[16891]: {"type":"log","#timestamp":"2018-04-17T08:37:39Z","tags":["warning","elasticsearch","admin"],"pid":16891,"message":"No living connections"}
I have tried to restart again
elasticsearch.service: Main process exited, code=exited, status=1/FAILURE
elasticsearch.service: Unit entered failed state.
elasticsearch.service: Failed with result 'exit-code'.
milenko : TTY=pts/1 ; PWD=/home/milenko ; USER=root ; COMMAND=/bin/journalctl -f
What does this output mean?
I do not understant what is wrong,I have the same problem.