[Code] 404 (Not found) [Description] 
The server can't find the requested page. For instance, the server often returns this code if the request is for a page that doesn't exist on the server. If you don't have a robots.txt file on your site and see this status on the Blocked URLs page in Google Search Console, this is the correct status. However, if you do have a robots.txt file and you see this status, then your robots.txt file may be named incorrectly or in the wrong location. (It should be at the top-level of the domain and named robots.txt.) If you see this status for URLs that Googlebot tried to crawl, then Googlebot likely followed an invalid link from another page (either an old link or a mistyped one).