Internal links point at error pages

What this means

Links on this page target URLs that answer with a 4xx or 5xx. Users following them hit a dead end, and search engines treat a page that routinely links into errors as poorly maintained. Unlike a broken external link, every one of these is fully within your control.

How to fix it

For each target, either restore the missing page, repoint the link at the URL that replaced it, or remove the link. If the destination was retired on purpose, redirect it to the closest surviving equivalent so existing inbound links keep working too.

Fix effort

This check needs review: the change can be drafted for you, but a person has to approve the wording or choose the target before it ships.

Authoritative source

https://developers.google.com/search/docs/crawling-indexing/http-network-errors