502 Bad Gateway nginx

By running “chcon -Rv --type=httpd_sys_content_t /opt/zammad/public/” as root I get a lot of errors:

chcon: can’t apply partial context to unlabeled file ‘assets’
changing security context of ‘/opt/zammad/public/403.html’

Anyway I ran the other commands and did a reboot, but still getting error 502, because 127:0.0.1:3000 is not reachable. What did I do wrong?