Would you like to know how to enable http2 + quic in nginx?
(...)
is someone already using it?
Cool!
This may be a site configuration problem.
Check you site is using correct templates, in CWP panel at "WebServer Settings -> WebServers Main Conf" for config all sites in your server, or "WebServer Settings -> WebServers Domain Conf" for a specific site config. These two menus rebuild configuration to use the correct certificate locations in your server.
Regards,
Netino