Error: Failure running 'service nginx start', exiting during installation

[Edi Septriyanto]

Install process exited with message

Error: Failure running 'service nginx start', exiting.

from journalctl -xe command gave

# journalctl -xe
-- Unit resolvconf-pull-resolved.service has begun starting up.
Aug 17 16:46:09 ucsg1.eslabs.id systemd[1]: Started resolvconf-pull-resolved.service.
-- Subject: Unit resolvconf-pull-resolved.service has finished start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- Unit resolvconf-pull-resolved.service has finished starting up.
-- 
-- The start-up result is RESULT.
Aug 17 16:46:28 ucsg1.eslabs.id systemd[1]: Starting A high performance web server and a reverse proxy server installed using LEMPer...
-- Subject: Unit nginx.service has begun start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- Unit nginx.service has begun starting up.
Aug 17 16:46:28 ucsg1.eslabs.id nginx[9196]: nginx: [emerg] invalid value "http_502" in /etc/nginx/fastcgi_cache:6
Aug 17 16:46:28 ucsg1.eslabs.id nginx[9196]: nginx: configuration file /etc/nginx/nginx.conf test failed
Aug 17 16:46:28 ucsg1.eslabs.id systemd[1]: nginx.service: Control process exited, code=exited status=1
Aug 17 16:46:28 ucsg1.eslabs.id sudo[2220]: pam_unix(sudo:session): session closed for user root
Aug 17 16:46:28 ucsg1.eslabs.id systemd[1]: nginx.service: Failed with result 'exit-code'.
Aug 17 16:46:28 ucsg1.eslabs.id systemd[1]: Failed to start A high performance web server and a reverse proxy server installed using LEMPer.

it seems a configuration error from the latest commit for /etc/nginx/fastcgi_cache config.