Why is a 404 page is cached as 200

Prerender will render and cache pages depending on the HTTP status they return. 

In the case of a soft 404 page, the page's content might notify users that the URL does not exist; however, if Prerender gets a 200 status from the page, it will be rendered and cached just like a 200 page. If your 404 page is cached as a 200 page, then the page returns a 200 HTTP status. 

How to check: 

• Open the URL you wish to check.
• Open Dev tools (CTRL+Shift+J on Windows , Option + ⌘ + J on Mac)
• Click on the Networks tab and check the status column of the first element of the list.

Related articles: 

- Status Codes

- 404 Checker: A Tool for Website Owners

- Why is a 404 page is cached as 200

- Are 404s and 301s included in the render counter