Nginx + PHP-fpm: Access to the script has been denied?

Question

PHP

Php-fpm says access denied, why? All permissions are 777, all user groups are www-data:www-data, there is an index.php file, the path is correct

config

server{
  listen 80;
  add_header x-dbg-80 1;

  # logging
  access_log /home/www-data/backend/logs/vk.access.log;
  error_log /home/www-data/backend/logs/vk.error.log warn;

  location /vk/callback {
    add_header x-dbg-80 2;

    alias /home/www-data/backend;
    index index.php;
    try_files $uri $uri/ /index.php?$args =404;

    # fastcgi settings
    include fastcgi_params;
    fastcgi_pass			       unix:/var/run/php/php7.4-fpm.sock;
    fastcgi_index			       index.php;
    fastcgi_buffers			       8 16k;
    fastcgi_buffer_size		       32k;
    fastcgi_split_path_info        ^(.+\.php)(/.+)$;
    fastcgi_param                  SCRIPT_FILENAME                    $request_filename;
  }
}

Answer 1

Check who is running Ngnx
Check who is the owner and who can read the file execute index.php
Maybe this is the problem