I get these error messages from Yandex.
The main mistake is “When accessing the page, the robot received 403”
http://joxi.ru/YmEZYgjHJy8JR2
This error does not occur on all of our sites.
Here is the Yandex support answer
The page https://xxxxxx.xx was indeed excluded from the search, because earlier it responded to robot requests with HTTP code 403. The problem was relevant, for example, when visiting the robot 2020-05-26 01:32:04. To find out the causes of the problem, you can contact the administrator of your site. Now the error does not occur, the page will be freely indexed by the robot and will be able to return to the search with subsequent updates to the search base as they are crawled by the robot.
Take a look at: Cloudflare waf blocking Yandex robot - #3 by convertiser
I have same problem.
Only one from all my sites return 403 error
I tried to create rules, add ASN and Yandex user agents to whitelist
later you can see that the robot visits the pages (or tries), but in the webmaster panel Yandex return a 403 error
I checked all similar topics on the forum and did not find a solution anywhere