@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