QUIC connection could not be established

[findmyname]

Oh noo I just realized that there was allowed firewall (FW) only for TCP to
port 443 :facepalm:
The http3 check is passing after FW adjustment.
Sorry for spam guys and girls.

P.S.: I'm still fighting with firefox and http3 but I'm sure I will figure
it out.

BR

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,292896,292901#msg-292901