Interesting coincidence.
my box with the DNS resolver problem- (has IPv address obviously)
PING6(56=40+8+8 bytes) 200x:1xx1:3xx4::1 –> ::1 (changed to obfuscate)
--- ::1 ping6 statistics ---
3 packets transmitted, 0 packets received, 100.0% packet loss
My customer box which works fine. (does not have IPv6 set up)
PING6(56=40+8+8 bytes) ::1 --> ::1
16 bytes from ::1, icmp_seq=0 hlim=64 time=0.521 ms
16 bytes from ::1, icmp_seq=1 hlim=64 time=0.353 ms
16 bytes from ::1, icmp_seq=2 hlim=64 time=0.459 ms