You should know that a server returns one of the various status codes for example errors for 0 4 and
5 0 3 when the user requests a specific resource problems may easily emerge from these situations.
Here are the main status codes which I suggest you should learn 200.
The server returns a correct answer 3 0 1 permanently moved the page has been moved to a new location
3 0 2 temporarily moved the page has been temporarily moved to a new location and may return to the
previous address in the future for 0 4.
Not Found The requested page was not found for 10 content deleted.
The page was not found because the content was intentionally removed without any intention of replacing
it.
5 0 3 service unavailable.
It is often used during site maintenance.
It can also occur when a plugin generates conflicts or in the event of a Script error which could impact
the accessibility of the entire Web site.
When Google board visits a page and gets a forum for error code it may remove the page from the search
results.
It will then try to verify if the content has returned as I often say to students forum for errors are
also a nuisance for users and we must try to avoid them as much as possible.
The two methods I recommend in order to find out if a Web site has these problems are search console
inside the panel.
There is a section with a list of broken links with all the pages involved.
However this report is often incomplete and only illustrative paid crawler.
The most famous tool is screaming frog which allows you to visit all the pages of a Web site within
a few minutes and then showing you a complete report of all the errors found but what happens when a
forum for error is discovered The approaches vary depending on the number of web pages involved and
the possibility of replacing these errors.
If it's a few dozen pages you can consider checking the links by hand and fixing them by entering the
correct address or by creating a new content to replace the missing page.
If on the other hand it's about hundreds or thousands of four or fours obviously it is a technical problem
and you should check where how and why the situation was created.
In my experience I discover similar situations.
Basically due to a relative infinite loop.
Now let's see the details the crawler follows each link on the web page and when it finds for example
a relative link in the sidebar such as a h ref equals article it will follow the address article slash
article where it will find the same link which this time will lead to Article slash article slash article.
This process will practically continue indefinitely following pages that do not exist.
Crawling was actually the core business of one of my previous startups.
The relative infinite loop situation often occurs in amateur or small Web sites.
Therefore it was necessary to contact a webmaster in order to inform him of the big problem that he
ignored.
Another delicate situation occurs during technical interventions performed on the Web site thus making
some content inaccessible.
If the bot passed during these minutes it wouldn't be able to view the correct content of the pages
and this might damage ranking positions even though in reality an hour later the web pages would be
fully functional in order to avoid such disasters.
I suggest showing a 5 0 3 error code to inform Google that we are working on a server and this way it
should try again later automatically.