Custom error pages and soft 404s TN-W19
Many sites configure a friendly 404 error page to be displayed instead of the web server’s default 404 page.
Problems occur if the custom error page returns a 200 OK HTTP status code instead of 404 Not Found, or redirects to an error page that returns 200 OK. Similar problems happen if missing pages cause a redirect to the home page.
The 200 OK status indicates to the browser that the page was found, so the custom error page is cached. This is a problem if the missing page is restored - the cached custom error page will be returned until the cache expires.
The 200 OK status means that Google cannot tell the difference between error pages and normal pages, and may either index your error pages, or reduce your site ranking.
The 200 OK status means that link checking tools cannot detect broken links.
A missing component file (JS/image/CSS) on a custom error page that returns 200 OK can result in an infinite loop, and denial-of-service on the web server. That happens because missing compontent on the error page causes a 404 which requests another copy of the error page, which triggers another 404 that requests another copy of the error page … and so on.
Note: You can see the HTTP status code returned in the Network tab of Chrome developer tools - click on the page in the list of resouces to see the Status Code.
See also: Google help for soft 404s
Applies To: SortSite Desktop 1.0 or later
Last Reviewed: December 19, 2016