Lost connection when accessing the site ERR_CONNECTION_TIMED_OUT, what is the reason?

Question

Nginx

I welcome everyone!

There is a site conditionally https://test.ru , periodically when entering this site, the ERR_CONNECTION_TIMED_OUT error occurs, and at the same moment and in the same subnet, users access this site without problems, and other sites also work stably. After some waiting, this user can use the site again. Tracking the moment is quite difficult, because. the error is rare, but creates big problems.

On the centos 7 server, we have nginx, php-fpm, mysql.

What I did:

1. At first I sinned on the ssl certificate, because people wrote that there could be problems precisely because of him. I changed the settings in different ways, disabled the certificate, tried another domain, the problem is the same.
   
2. I changed nginx settings, set default ones, and so on, the problem was not solved.
   
3. I decided that the problem is not in the server, but local. Changed the router, nothing has changed.
   
4. I managed to catch the moment several times, I went to the server, ran tcpdump, received only a connection request https: Flags [S], but the server did not give a response for a while, then it automatically received ASK
   
5. Firewall turned off
   
6. DNS did not change, in theory one could still try to install from Google or Yandex, but why then does everything work on the neighbors in the same subnet?
   

So comrades, where to dig?

While I sin on the provider, tk. a couple of times I managed to catch the moment and launch Opera with VPN from the same computer, the site opened. Googled, the topic is quite common, but all solutions are individual.

There were also such options:
ipconfig / registerdns
ipconfig / release
ipconfig / all
ipconfig / flushdns
ipconfig / renew
netsh int ip set dns
netsh winsock reset

yes, after these procedures it started working for a while, but not a fact, maybe just while I reset DNS settings, the connection has already been restored.

Answer 1

Did you update the time on the client?