Check Order Tracking Method
If your client is running the ranking tracking from the Google search results page, it should be explained that this is the wrong method. The Google algorithms are enough for each user to have different conditions, so that a page appears in different order to the user.
Check for Recent Changes
If you receive a mail titled that our website will continue to work with the most up-to-date technology tomorrow after the software update is done tonight, you may not know that the website is temporarily receiving noindex tags for only a few hours of work. Worst of all, it may be even worse that the small tag is forgotten there after the update.
A large number of recent link losses can trigger a decline in your traffic, which may be reflected in ranking performance. Sometimes Webmasters who have migrated to Https and who forget to redirect or forget to redirect the URL structure and cause redirection can trigger these link losses.
Check Security Status
Sometimes even the most secure systems can be captured, misused. Such events will adversely affect your ranking performance. Beyond standard safety procedures, controls that provide extra protection can save lives. If you are faced with the ever-deteriorating ranking performance beyond variability, it is better to have a professional security check.