One of the annoyances with #NAT64 is that when some site publishes an #IPv6 AAAA record, but their IPv6 server is down and the IPv4 server is up, there's no "happy eyeballs" fallback to IPv4. Because the AAAA record exists, #DNS64 doesn't provide a mapping to IPv4.

It can be worked around by manually adding an /etc/hosts entry for the broken site.

Today's broken site is www.fsf.org. Hey @fsf - your IPv6 server is refusing connections 😉