Oh I understand it now. Thank you for information.

Website.

So probably it’s about my network. Thanks for reply.

I used a bunch of distributions (like Gentoo, Arch, Slackware, Debian etc.). Then I created a distribution-like system with LFS -BLFS and now using itbecause I want to see how Linux works in a detailed way. It’s a little painful but it’s not a problem if you are a masochist person who doesn’t have to do anything else.