Redirecting to my page

Hey, so I have CNAME DNS record with a name “www.qvadro-joga.cz” and value of “[adamvsb.github.io]” which should be correct as I am hosting my page on github (and when I write “www.qvadro-joga.cz” it works). But even though I added .htaccess file to redirect anyone that doesnt write “www” to my page it just doesnt work and it says that it couldnt find DNS address of this server. So I wanted to ask where could be the problem or what am I missing or if there is some problem on github?
Thank you for your time,
Adam

.htaccess file:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.qvadro-joga.cz [NC]
RewriteRule ^(.*)$ http://qvadro-joga.cz/$1 [L,R=301]

.htaccess is for Apache (and possibly other) servers. Such a file is ignored by Netlify. You need to use a _redirects file as outlined in

Also I see qvadro-joga.cz is using Netlify DNS. This is intended for sites hosted on Netlify, not on other platforms.

If you want to use a custom domain on a GitHub Pages site, I suggest looking at the custom domains documentation on GitHub Pages