And here comes the recipe to find out what the reason is:
A significant drop in Google ranking can have a wide variety of causes. However, these are increasingly difficult to identify. Google now evaluates more and more individual sections and regions of a website, such as individual directories, subject areas or search queries. So if the homepage is affected by a ranking drop, it may be that only some sections are affected – but others gain at the same time.
Basically, the more extensive a website is, the more important it becomes to examine the individual changes that happen on the page. To get to the bottom of these changes in more detail, it is usually done in three steps: find the affected subject area, or pages, interpret the changes, and adjust the SEO measure.
PART 2 to follow soon