package:nginx-core:(not installed)
Setting up nginx-core (1.10.3-0ubuntu0.16.04.2) ...
Job for nginx.service failed because the control process exited with error code. See "systemctl status nginx.service" and "journalctl -xe" for details.
invoke-rc.d: initscript nginx, action "start" failed.
● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Tue 2018-02-06 11:44:58 IST; 10ms ago
  Process: 15033 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=1/FAILURE)
  Process: 15030 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)

Feb 06 11:44:57 kashyap nginx[15033]: nginx: [emerg] bind() to [::]:80 fail...e)
Feb 06 11:44:57 kashyap nginx[15033]: nginx: [emerg] bind() to 0.0.0.0:80 f...e)
Feb 06 11:44:57 kashyap nginx[15033]: nginx: [emerg] bind() to [::]:80 fail...e)
Feb 06 11:44:58 kashyap nginx[15033]: nginx: [emerg] bind() to 0.0.0.0:80 f...e)
Feb 06 11:44:58 kashyap nginx[15033]: nginx: [emerg] bind() to [::]:80 fail...e)
Feb 06 11:44:58 kashyap nginx[15033]: nginx: [emerg] still could not bind()
Feb 06 11:44:58 kashyap systemd[1]: nginx.service: Control process exited, ...=1
Feb 06 11:44:58 kashyap systemd[1]: Failed to start A high performance web ...r.
Feb 06 11:44:58 kashyap systemd[1]: nginx.service: Unit entered failed state.
Feb 06 11:44:58 kashyap systemd[1]: nginx.service: Failed with result 'exit...'.
Hint: Some lines were ellipsized, use -l to show in full.
dpkg: error processing package nginx-core (--configure):
 subprocess installed post-installation script returned error exit status 1