When chef is installed on a server where Apache is already running on a port 80, proceed as follow to prevent the chef server to listen on the port 80.
Navigate in the chef webserver settings directory
cd /var/opt/opscode/nginx/etc
Edit the configuration file
vi nginx.conf
Comment the following lines
# server {
# listen 80;
# access_log /var/log/opscode/nginx/rewrite-port-80.log;
# return 301 https://$host$request_uri;
# }
Restart chef and check that no error is returned anymore
chef-server-ctl restart nginx chef-server-ctl tail nginx