@planner you bet it right! I want ONLY nodebb to run @forum.caffeh.com, planning to install YUI or Docpad in the caffeh.com and to let my server IP empty (or default nginx file)
I think my problem is that I have disabled all virtualhost support, that forum is my "default virtual host". How to fix that?

Finally there is a light!
I do not remember the steps exactly, but mainly if someone having the same problem (running CentOS 6) you need to:

nano /etc/nginx/conf.d/virtual.conf

add the code what was already mentioned many time:
https://github.com/designcreateplay/NodeBB/wiki/Configuring-nginx-as-a-proxy-to-NodeBB
So my problem was that I was not able to figure out the right files to edit! (when you guide people, you might always remind the path or mention exact file need to be edited - what is obvious for you, might be obscure for others)
Now the forum works fine, but there is a new problem:
I want to run nodebb only at http://forum.caffeh.com (as sub-folder or sub-domain) but I can see it is same running at the root (caffeh.com ) and at the server IP 37.59.29.104
My virtual.conf file:

server {
listen 80;

server_name forum.caffeh.com;

location / {
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_set_header X-NginX-Proxy true;

    proxy_pass http://127.0.0.1:4567/;
    proxy_redirect off;

}

}

@kelso Thank you for the effort to answer me
I am running only nginx (I deactivated httpd via cpanel) / Centos 6, (by the way I can't find this config.json file ?)

Any useful information how to run nodebb forum without the :4567 port ?

@planner it is not a cloud... it is a dedicated server from OVH... (the cpanel mainly for my customer, they did not like virtualmin nor ispaconfig)

I would still need the apache, because of the cpanel (at least I know that I need the cpanel )
I will try to work around using that tuts from DigitalOcean. Thx bentael!

@bentael I am running CentOS 6

That s good question, basically I do have Cpanel running (can it run only on Nginx?) I setup this server just to install NodeBB.

It would be useful for newbies to have simple and clear step-by-step guideline how to setup Nginx as a front end proxy for Apache.

@frissdiegurke
Thank you, I am using redis db... I did re-install nodebb, looks easy and fine: http://forum.caffeh.com:4567/
Now my real problem will be again, how to configure nginx as proxy for apache server... I tried (for last 5 days) all existing solution what everyone suggested in vain
but I AM NOT GOING TO GIVE UP, I love NodeBB

Thank you for the quick answer, was doing same, but thought might be some other files to delete

Can someone point me to how to totally remove nodebb from the server in order to perform new fresh install?

yes I did.

root@server [/etc/nginx/vhosts]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

I went to /etc/nginx/vhosts/forum.caffeh.com
I copied and pasted your code as it is, nothing works, am I missing something else?

cat /etc/nginx/vhosts/forum.caffeh.com

It is already there, could you please check what is the problem?

server {
          error_log /var/log/nginx/vhost-error_log warn;
          listen 37.59.29.104:80;
          listen [::]:80;
          server_name forum.caffeh.com www.forum.caffeh.com;
          access_log /usr/local/apache/domlogs/forum.caffeh.com-bytes_log bytes_log;
          access_log /usr/local/apache/domlogs/forum.caffeh.com combined;
          root /home/caffeh/public_html/forum;
          #location / {
          location ~*.*\.(3gp|gif|jpg|jpeg|png|ico|wmv|avi|asf|asx|mpg|mpeg|mp4|pls|mp3|mid|wav|swf|flv|html|htm|txt|js|css|exe|zip|tar|r$
          expires 1M;
          try_files $uri @backend;
          }
          location / {
          error_page 405 = @backend;
          add_header X-Cache "HIT from Backend";
          proxy_pass http://37.59.29.104:8081;
          include proxy.inc;
          include microcache.inc;
          }
          location @backend {
          internal;
          proxy_pass http://37.59.29.104:8081;
          include proxy.inc;
          include microcache.inc;
          }
          location ~ .*\.(php|jsp|cgi|pl|py)?$ {
          proxy_pass http://37.59.29.104:8081;
          include proxy.inc;
          include microcache.inc;
          }
          location ~ /\.ht {
          deny all;
          }
        }

Hi,
I tried to follow that tuts, here the output of my cat /etc/nginx/vhosts/caffeh.com

server {
error_log /var/log/nginx/vhost-error_log warn;
listen 37.59.29.104:80;
listen [::]:80;
server_name caffeh.com www.caffeh.com;
access_log /usr/local/apache/domlogs/caffeh.com-bytes_log bytes_log;
access_log /usr/local/apache/domlogs/caffeh.com combined;
root /home/caffeh/public_html;
#location / {
location ~..(3gp|gif|jpg|jpeg|png|ico|wmv|avi|asf|asx|mpg|mpeg|mp4|pls|mp3|mid|wav|swf|flv|html|htm|txt|js|css|exe|zip|tar|r$
expires 1M;
try_files $uri @backend;
}
location / {
error_page 405 = @backend;
add_header X-Cache "HIT from Backend";
proxy_pass http://37.59.29.104:8081;
include proxy.inc;
include microcache.inc;
}
location @backend {
internal;
proxy_pass http://37.59.29.104:8081;
include proxy.inc;
include microcache.inc;
}
location ~ .*.(php|jsp|cgi|pl|py)?$ {
proxy_pass http://37.59.29.104:8081;
include proxy.inc;
include microcache.inc;
}
location ~ /.ht {
deny all;
}
}

cat /home/caffeh/public_html/forum/config.json

{
"base_url": "http://caffeh.com/",
"port": "4567",
"use_port": false,
"secret": "62914b18-6014-443b-85cc-124f9362417d",
"bind_address": "localhost",
"database": "redis",
"redis": {
"host": "127.0.0.1",
"port": "6379",
"password": "hidden psw",
"database": "0"
},
"bcrypt_rounds": 12,
"upload_path": "/public/uploads",
"relative_path": ""
}

I am willing to have my forum at http://forum.caffeh.com in the root ( www.caffeh.com ) I will install docpad as blog / portal
so far, it works only with port: http://forum.caffeh.com:4567/

progress:
http://caffeh.com:4567/
I was installing all the time the nodebb in /forum why it is in the root ?
And why I need to add the port 4567 in order to see? I am running nginx

Somehow I managed to solve that issue...
Now I again stuck somewhere, I installed most of what is supposed to be there, and I started most of the service what is supposed to be running, but for now I can't figure out which direction to proceed: http://caffeh.com/forum/

I am trying to install NodeBB at [http://caffeh.com ](link url) but when I run command
node app --setup
I get into error:
error: Auth error: Error: ERR invalid password
Of course I did setup my password in /etc/redis.conf
Thank you in advance for any support !

Thx, I got:

[root@ns3334501 ~]# forever restart
-bash: forever: command not found