What's wrong with letsencrypt certificate?

Question

CentOS

I installed certbot on centos 7 , everything works fine in browsers, letsencrypt certificates are updated, there are no problems, but when I try to check the site on validator.w3.org , I get an error, 500 Can't connect to domain.ru:443 (certificate verify failed) . I don’t know what to do, maybe someone has already come across it, tell me where to dig? I'm afraid that this may affect the indexing

Answer 1

here's what we managed to dig
up https://lists.w3.org/Archives/Public/www-validator...
https://lists.w3.org/Archives/Public/www-validator...
In short, it says that this is a problem on the https://validator.w3.org/ side , to be more precise, it does not support SNI (Server Name Indication), and it is also recommended to use https://validator.w3.org/nu/
to influence the indexing, it seems, not should, since SNI is supported by Google and Yandex bots.