A series of issues.

I suspect the cause might be the default DNS servers provided by your internet service provider.



https://www.perplexity.ai/search/chto-oznachaet-oshibka-ns-erro-_0a5yLBgQmmqnr3gYSC25g

If you are using the default DNS servers from your internet provider, try using Google's DNS: 8.8.8.8 and 8.8.4.4, or Cloudflare's DNS: 1.1.1.1 and 1.0.0.1.

Here's a guide for Google DNS:
https://cloudparser.ru/wiki/google-dns

And here's one for Cloudflare:
https://one.one.one.one/ru-RU/dns/

I set it up in the router, but there were no changes.

In general, this seems to be some kind of isolated case, a bug, an error, or perhaps a deliberate restriction imposed by the provider, probably on my end. I'm sorry that I wasted your weekend, I acted impulsively and behaved rudely. Please forgive me.
I'm tired and I want to take a break from the endless searching.