What is the strange behavior of Letsencrypt pinging its certificates?

Question

Nginx

Judging by the logs, every 3 hours the server pings itself (?) to checks that I don’t understand, I see that the legs are growing from the letsencrypt, but I don’t understand where exactly.

Answer 1

maybe someone is trying to get a certificate for your domain

Answer 2

Well, why not? What a pity for you choli :)
Although the path is strange, it seems that they are checking for some sign from phishing sites - that is, they are looking for phishing that use their certificates and then they will ban serts.

Answer 3

Judging by the history, someone else had the domain with their own certificate, apparently there is a script for auto-renewal of the certificate, but it does not pass validation:
https://crt.sh/?q=finand.ru
and you registered the domain after it was released.