404 Page Description & How to Fix
404 – Not Found is one of the most common 4xx errors and indicates that the requested URL does not exist.
Links pointing to the 404 URLs are widely known as "broken links".
404 URLs on your website damage the user experience, as people cannot access the page or file via a link they click. Besides, internal links to 404 URLs create unnecessary "dead ends" for the search engine crawlers and can waste your crawl budget.
How to fix
You should review the internal outgoing links to all the 404 pages reported and either remove these links or replace them with relevant links to live pages.
Alternatively, you can set the appropriate 301 redirects. It is especially important for the 404 pages with a decent number of external backlinks.