No luck with systemctl restart rockstor.
/var/log/nginx/error.log contains:
2016/05/04 07:41:12 [emerg] 14606#0: no “events” section in configuration
2016/05/04 07:41:13 [emerg] 14636#0: no “events” section in configuration
2016/05/04 07:41:16 [emerg] 14794#0: no “events” section in configuration
2016/05/04 07:41:19 [emerg] 14861#0: no “events” section in configuration