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.
How to fix it?
You can find a guide on how to solve this issue here: Best practices
Related articles:
- 404 Checker: A Tool for Website Owners