Google’s John Mueller replied on Twitter in response to a question that a good number of the 404 error codes which Google picks up on are not the webmasters fault.
He also told that many people link oddly or use broken code which result in the 404 error.
Below is John’s tweet:
Most 404s aren't the site's fault; people (+sites) link in the weirdest, broken ways. Hiding the errors doesn't seem right
— John ☆.o(≧▽≦)o.☆ (@JohnMu) January 3, 2017
The 404 or Not Found error message is a HTTP standard response code which indicates that a user was able to communicate with a given server, but the server couldn’t find what was requested.
In other words, when a user attempts to follow a dead or broken link, the website hosting server will typically generate a “404 Not Found” error.
It shows that not every time it is a webmaster mistake when a 404 error shows up. Sometimes it can be a person mistake or maybe cause of a broken code.
So if you ever see 404s, don’t take it individually, every site has them.
You can see the whole discussion at Twitter.