I added listen 6235; to server block, but it's not working. I can't access it.
need to whitelist and open port in CSF Firewall to allow the traffic through via /etc/csf/csf.conf TCP_IN and TCP_OUT and if IPv6 enabled also TCP6_IN and TCP6_OUT option see CSF Firewall - Centmin Mod - Menu based Nginx installer for CentOS servers and step 4 in Getting Started Guide