Grafana instance is not working! after installation i started the service grafana-server but showing some error

grafana-server.service - Grafana instance
Loaded: loaded (/usr/lib/systemd/system/grafana-server.service; enabled; vendor preset: enabled)
Active: inactive (dead) (Result: exit-code) since Tue 2019-07-30 10:51:21 IST; 615ms ago
Docs: http://docs.grafana.org
Process: 28724 ExecStart=/usr/sbin/grafana-server --config={CONF_FILE} --pidfile={PID_FILE_DIR}/grafana-server.pid --packaging=deb cfg:defau
Main PID: 28724 (code=exited, status=1/FAILURE)

PLEASE HELP ME TO FIX THIS ERROR

What is the error message in the grafana log file ?