Solution for NGINX error 404 and "FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream, client:"

gistfile1.txt

add the line fastcgi_param

root /var/html/www/my-website

location ~ \.php$ { 
  # return 200 $document_root$fastcgi_script_name; // uncomment and download the php file and read the link inside the file. Make the necessary corrections
  # fastcgi_param SCRIPT_FILENAME /var/html/www/my-website/$fastcgi_script_name;
  
  fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}