If you're seeing this message in the Technical/Custom 404 component, then our 404 checks have failed:
The most common cause of this is that your site is returning a 'soft 404'. It may display a 404 message, but the server is returning a 200 Status Code. To check this, there are a number of free 404 checking utilities available online you can use, but here's one as an example: http:// 404checker.com/404-checker. Enter your URL and if you see this response, then you're producing a 'soft 404':
The second reason why your site may be failing this check is that your 404 page is not returning any custom CSS. Standard 404 pages are pretty dull and make for poor user experience (as do lots of pages not found in general!). If you're short of ideas for customising your 404 page, then use sites like http:// fab404.com/ for inspiration.
If you fix the problem, the system will automatically check the status again the following day (as this is part of our daily health check processes).
If the site does find a Custom 404 page, the component score will change to 100% and you will also see this message if you look at the related task table (click on the green Add/Edit Task button):
Why should you bother to fix this? Well, here are some of the effects this issue can have:
i) You're wasting crawl bandwidth - although Google doesn't actually specify a set number of pages for each site that they'll crawl in a fixed time period, you are wasting your chance to get your good content indexed (and therefore potentially ranking) if Google is indexing these soft 404 pages and it will do, because you're returning a 200 code, telling googlebot that the page is fine.
ii) It is providing a poor user experience - you're not helping your users find what they'e looking for a custom 404 page can be entertaining and include suggestions and/or an internal search box
For further reading, check out Google's official advice on the subject of 404s
There's also some good tips on this thread - http:// community.seoworkers.com/threads/173-Soft-404-Error-Pages
Meta Refresh Re-direction
Some of you may also encounter our software reporting a 404 not found where you have used Meta Refresh re-direction.
When we request a non-existent page, we get a response with status code 404, and content
<meta HTTP-EQUIV="REFRESH" content="0; url= [https://www.example.com/404.php](https://www.vpsnine.com/404.php)">
We then check that content looking for custom styling to indicate that this is a custom 404 page, and can't find any. Because the http status code is 404, we interpret this as meaning that we have received the final response from the server for that http request.
If the request for a non-existent page was returned with a redirect http status code (e.g. 301) and a redirect location of https://www.example.com/404.php, we would follow that redirection, and correctly detect the custom 404 page. This is the W3C recommended way of handling redirection, rather than using meta refresh tags.