How to Fix Soft 404 Errors in WordPress

This last week I have been getting a lot of notifications from Google Search Console about a drastic increase in soft 404 errors. Usually, whenever you get a notification directly from Google there is something you need to fix. Generally you should never ignore these. Check out one way below on how to fix soft 404 errors in WordPress. What are Soft 404 Errors?
You are probably all familiar with standard 404 errors, which means a page doesn’t exist. A soft 404 error occurs when a non-existent page displays a page not found message to anyone trying to access it, but fails to return a HTTP 404 status code. They can also occur when the non-existent page redirects users to an irrelevant page, such as the homepage, instead of returning a HTTP 404 status code. The important thing to remember here is that the content of a web page is entirely unrelated to the HTTP response returned by the server.
Google has a great analogy to explain soft 404 errors:
Just because a page displays a 404 File Not Found message doesn’t mean that it’s a 404 page. It’s like a giraffe wearing a name tag that says “dog.” Just because it says it’s a dog, doesn’t mean it’s
Source: https://managewp.org/articles/14357/how-to-fix-soft-404-errors-in-wordpress

source https://williechiu40.wordpress.com/2017/02/08/how-to-fix-soft-404-errors-in-wordpress/