I am a very weird situation.
Below is what I have done on my centos 7 box. I have nginx which works perfectly fine with a normal php application. Next via composer I just tried to install slim framework.

composer create-project slim/slim-skeleton app.
Next I tried to change the ownership via this command

chown nginx:nginx app/
next I did the chmod mod command
chmod 755 app/
next step I cd into the app folder
and ran this command
chmod 644 *

Below is my nginx.conf for now.

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

# Load dynamic modules. See /usr/share/nginx/README.dynamic.
#include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    server_tokens off;
    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;

  include             /etc/nginx/mime.types;
    default_type        application/octet-stream;

    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/blockuseragents.rules;
    limit_conn_zone $binary_remote_addr zone=addr:5m;
    server {
        listen       80 default_server;
        listen       [::]:80 default_server;
        server_name  _;
        server_tokens off;

        #root         /usr/share/nginx/html;
        root /var/www/html/;
        index index.php index.html home.html;
        # Load configuration files for the default server block.
        #include /etc/nginx/default.d/*.conf;
        include /etc/nginx/default.d/*.conf;


        location ~ ^/app {

          try_files $uri $uri/ /app/public/index.php$is_args$args;
        }

        location ~ .php$ {
         include fastcgi.conf;
         fastcgi_index index.php;
         fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
         fastcgi_intercept_errors on;
         fastcgi_pass 127.0.0.1:9000;
        }
 limit_conn addr 3;




    }

The weird part now when I type like this

http://myip/apiv5 I get 403 forbidden but when I type example like this.

http://myip/apiv5/token . I am suspecting some permission error is causing this to mess up. How can I enable it to work perfectly?

<?php
if (PHP_SAPI == 'cli-server') {
    // To help the built-in PHP dev server, check if the request was actually for
    // something which should probably be served as a static file
    $url  = parse_url($_SERVER['REQUEST_URI']);
    $file = __DIR__ . $url['path'];
    if (is_file($file)) {
        return false;
    }
}

require __DIR__ . '/../vendor/autoload.php';

session_start();

// Instantiate the app
$settings = require __DIR__ . '/../src/settings.php';
$app = new \Slim\App($settings);

// Set up dependencies
$dependencies = require __DIR__ . '/../src/dependencies.php';
$dependencies($app);
// Register middleware
$middleware = require __DIR__ . '/../src/middleware.php';
$middleware($app);

// Register routes
$routes = require __DIR__ . '/../src/routes.php';
$routes($app);

// Run app
$app->run();