I was trying to help a friend set up with the free service and tried to use IPv6 address: 2a0d:2a00:1:: and 2a0d:2a00:2:: but lost Internet connectivity. They use an ISP Spectrum provided modem with wifi. When we reverted the IPv6 DNS setting they got internet back. Why would it work with the full length paid IPv6 address but not the shorter version?