I know there are many such questions on stack exchange. But nothing could help to the scenario that I have.
Here is my situation.
I have a webserver running on apache2 listening to the port numbers 7080 and 7081. I have used reverse-proxy method on my server and installed nginx which is listening to the port 80. So now nginx is the front end. I have my wordpress website running on http://www.example.com. 
Now I am trying to install node.js app on my server which I could not. It makes sense because port 80 is being used by nginx. 
I referred to the following posts on SO
Apache and Node.js on the Same Server
I tried the following
    upstream example.com/my-app {
    server 1**.*.**.**:3010;
}
# the nginx server instance
server {
    listen 1**.*.**.**:80;
        server_name example.com/my-app;
    server_name www.example.com/my-app;
    server_name ipv4.example.com/my-app;
    access_log off;
    # pass the request to the node.js server with the correct headers and much more can be added, see nginx config options
    location / {
      proxy_set_header Host             $host;
      proxy_set_header X-Real-IP        $remote_addr;
      proxy_set_header X-Forwarded-For  $proxy_add_x_forwarded_for;
      proxy_set_header X-Accel-Internal /internal-nginx-static-location;
      proxy_pass http://example.com/my-app;
      proxy_redirect off;
    }
location /internal-nginx-static-location/ {
        alias      /var/www/vhosts/example.com/httpdocs/node;
        access_log /var/www/vhosts/example.com/httpdocs/node/statistics/logs/proxy_access_ssl_log;
        add_header X-Powered-By PleskLin;
        internal;
    }
 }
I wrote the above conf in a file and included it in /etc/nginx/conf.d/xzzeaweae_nginx.conf.
It is not working. but the app is running properly on 1++.+.++.++:3010 though.
My directory structure.
/var/www/vhosts/example.com/httpdocs/
my wordpress website root directory : /var/www/vhosts/example.com/httpdocs/
my nodejs app directory: /var/www/vhosts/example.com/httpdocs/my-nodejsapp-folder/
UPDATE
Here is my reverse proxy config for my apache application
server {
    listen +++.+.++.++:80 ;
    listen ++.+.+++.++:80 ;
    location / {
        proxy_pass http://127.0.0.1:7080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}
Since I have more than one website running on my server,
I have reverse proxy config for every website.
Here it is for one of my website
server {
    listen +++.+.++.++:443 ssl;
    server_name example.com;
    server_name www.example.com;
    server_name ipv4.example.com;
    ssl_certificate             /opt/psa/var/certificates/certaqnxHd2;
    ssl_certificate_key         /opt/psa/var/certificates/certaqnxHd2;
    ssl_session_timeout         5m;
    ssl_protocols               SSLv2 SSLv3 TLSv1;
    ssl_ciphers                 HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers   on;
    client_max_body_size 128m;
    location / { # IPv6 isn't supported in proxy_pass yet.
        proxy_pass https://+++.+.++.++:7081;
        proxy_set_header Host             $host;
        proxy_set_header X-Real-IP        $remote_addr;
        proxy_set_header X-Forwarded-For  $proxy_add_x_forwarded_for;
        proxy_set_header X-Accel-Internal /internal-nginx-static-location;
        access_log off;
    }
    location /internal-nginx-static-location/ {
        alias      /var/www/vhosts/example.com/httpdocs/;
        access_log /var/www/vhosts/example.com/statistics/logs/proxy_access_ssl_log;
        add_header X-Powered-By PleskLin;
        internal;
    }
}
server {
    listen +++.+.++.++:443 ssl;
    server_name webmail.example.com;
    ssl_certificate             /opt/psa/var/certificates/certaqnxHd2;
    ssl_certificate_key         /opt/psa/var/certificates/certaqnxHd2;
    ssl_session_timeout         5m;
    ssl_protocols               SSLv2 SSLv3 TLSv1;
    ssl_ciphers                 HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers   on;
    client_max_body_size 128m;
    location / { # IPv6 isn't supported in proxy_pass yet.
        proxy_pass https://+++.+.++.++:7081;
        proxy_set_header Host             $host;
        proxy_set_header X-Real-IP        $remote_addr;
        proxy_set_header X-Forwarded-For  $proxy_add_x_forwarded_for;
        access_log /var/www/vhosts/example.com/statistics/logs/webmail_access_ssl_log;
    }
}
server {
    listen +++.+.++.++:80;
    server_name example.com;
    server_name www.example.com;
    server_name ipv4.example.com;
    client_max_body_size 128m;
    location / { # IPv6 isn't supported in proxy_pass yet.
        proxy_pass http://+++.+.++.++:7080;
        proxy_set_header Host             $host;
        proxy_set_header X-Real-IP        $remote_addr;
        proxy_set_header X-Forwarded-For  $proxy_add_x_forwarded_for;
        proxy_set_header X-Accel-Internal /internal-nginx-static-location;
        access_log off;
    }
    location /internal-nginx-static-location/ {
        alias      /var/www/vhosts/example.com/httpdocs/;
        access_log /var/www/vhosts/example.com/statistics/logs/proxy_access_log;
        add_header X-Powered-By PleskLin;
        internal;
    }
}
server {
    listen +++.+.++.++:80;
    server_name webmail.example.com;
    client_max_body_size 128m;
    location / { # IPv6 isn't supported in proxy_pass yet.
        proxy_pass http://+++.+.++.++:7080;
        proxy_set_header Host             $host;
        proxy_set_header X-Real-IP        $remote_addr;
        proxy_set_header X-Forwarded-For  $proxy_add_x_forwarded_for;
        access_log /var/www/vhosts/example.com/statistics/logs/webmail_access_log;
    }
}
Note: sites-available and sites-enabled files are present inside apache2. Not in nginx.
I want my nodejs app to run on example.com/my-nodejsapp-folder/ without any port number.
Any help would be highly appreciated.
 
     
     
    