For what reason can a site drop sharply in Yandex search results?

Question

Yandex

Since September 1, the position of the site in the search results has fallen sharply, therefore the number of transitions has decreased by about 10 times. There were no drastic changes on the site that would have led to such "sanctions" from Yandex. Advertisements, etc. did not post. Everything is fine with other search engines.

Answer 1

Google "ban, pessimization, AGS"

Answer 2

Selling links through link exchanges: Sape and others like them.

Answer 3

1. If the content is not unique, it could fall under the ACS filter
   
2. If you do not sell links from the site, then there is a variant of mistakenly falling under the filter. Over time, it can get out of the filter itself, but it's better to write a letter to Yandex.