Since I can't check IPv6 connection easily (since here in South Korea ISPs don't allocate IPv6es to residential internet) I forgot to check server's IPv6 connection but while check Arch mirror ranking, I found out that my server's IPv6 was dead. It is now fixed with DHCP IP rerequest. Sorry for any inconveniences. (I doubt any happened since IPv4 is alive and well, who uses IPv6 anyways?)

Sent from my Mac with EndeavourOS with IPv4