Logstash not logging & failing after start of elasticsearch

Here is the process:

sudo service logstash start

sudo service logstash status

     logstash.service - logstash
       Loaded: loaded (/etc/systemd/system/logstash.service; disabled; vendor preset                                                                                                                                                              : disabled)
       Active: **active** (running) since Fri 2020-09-04 13:43:05 IST; 8s ago

sudo service elasticsearch start

Starting elasticsearch (via systemctl):                    [  OK  ]

sudo service elasticsearch status

elasticsearch.service - Elasticsearch
   Loaded: loaded (/usr/lib/systemd/system/elasticsearch.service; disabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/elasticsearch.service.d
           └─startup-timeout.conf
   Active: **active** (running) 

sudo service logstash status

logstash.service - logstash
   Loaded: loaded (/etc/systemd/system/logstash.service; disabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Fri 2020-09-04 13:46:24 IST; 1min 11s ago
  Process: xxxxx ExecStart=/usr/share/logstash/bin/logstash --path.settings /etc/logstash (code=exited, status=1/FAILURE)
 Main PID: xxxxx (code=exited, status=1/FAILURE)

Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Unit logstash.service entered failed state.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: logstash.service failed.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: logstash.service holdoff time over, scheduling restart.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Stopped logstash.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: start request repeated too quickly for logstash.service
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Failed to start logstash.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Unit logstash.service entered failed state.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: logstash.service failed.

Now, When i visit /var/log/logstash/logstash-plain.log it is not updated.