Reasons that could lead to a drop in your Google Website Ranking
Recent Changes in Your Website
Recently, you made major changes to the content of your website, which may have led a drop in rankings. These changes can include moving or revamping your website, as well as adding of a few extra pages.
Drops in SEO rankings may occur without your fault. Perhaps it's a technical issue on the search engine's end. Or perhaps it's challenging to crawl and index your website.
The algorithms used by search engines to rank webpages keep getting updated. So, if a search engine updates its algorithm, your website's rating may suffer as a result.