4XX Errors are HTTP response status codes returned by a server in response to a client request. It basically means that the request contains bad syntax or cannot be fulfilled. In other words, these errors typically occur when a URL has restricted access or rights, or simply doesn't exist.
How to verify 4XX Errors
If you're unsure whether our site auditor is reporting correctly, you can easily verify the status of your URL at https://httpstatus.io.
To do this, navigate to the SEO --> Site Auditor dashboard module. Click "4XX Errors" to see more information about which URLs have been flagged with this issue.
The dashboard will show you a list of URLs for which the site auditor has found 4XX errors.
The text in grey below the title of the page will indicate this page's URL. Copy this link to your clipboard and click the title of the page above to view the type of 4XX error found by our auditor:
A new dashboard will open with a slide-out panel on the right containing details of the 4XX error:
If you want to verify that this is correct, open a new tab on your browser and go to https://httpstatus.io, then paste the URL you've copied to your clipboard. If this page confirms a 400 error, then we're reporting it correctly at our end.
What are the most common 4XX Errors?
Some of the most common 4XX errors that our site auditor will report are:
401 Error: Authorization required
403 Error: Forbidden to access the page
404 Error: Page does not exist
408 Error: Request timeout