ls What’s the answer?
Does modifying the default page count as customization?

Several ways:

• Modify location:

location /my_blog {
    error_page    404 = /blog_article_not_found.html;
}

• Modify web site

server {
    listen 80;
    error_page  404  /website_page_not_found.html;
    ...

• Several errors on the same page

location /my_blog {
    error_page 500 502 503 504 = /server_error.html
}

Source:
http://stackoverflow.com/questions/10...

Find the default 500 page and change it

I would like to add to the criticism above, why don’t you go to the official website to check out nginx, an artifact with such a large number of users:
http://wiki.nginx.org/HttpCoreModule

Check the navigation column on the right, you will find everything you want, of course you want it; error_page must also be there