Google’s John Mueller said in a webmaster hangout on YouTube that Google will drop pages from its index if server errors persist for a longer period:
“If we see server errors persisting for a longer period of time, that could be I would guess around three four or five days, maybe a week or so, then what will happen is:
We will think that these server errors are actually permanent errors and we will drop those pages from our index and treat them more like a a 404 page where we say well every time we try to access this page the server tells us there’s an error so maybe we should stop accessing this page so much maybe we should stop showing it in the search results.”
For that reason, it is important to ensure that your web pages do not show the wrong HTTP status codes.
Remove server error codes from your web pages
The website audit tool in SEOprofiler checks the HTTP status codes of your web pages. For example, a page might deliver a 5xx server error status code although it looks fine in your browser. In that case, Google will remove the page from its index: